Aptitude

Aptitude Questions
1.One of the following is my secret word:AIM DUE MOD OAT TIE.With the list in front of you, if I were to tell you any one of my secret word, then you would be able to tell me the number of vowels in my secret word.Which is my secret word?
Ans.TIE

2.In the following figure:A B C
                                              D
                                              E F G
                                                       H
                                                       I
Each of the digits 1, 2, 3, 4, 5, 6, 7, 8, and 9 is:
a)Represented by a different letter in the figure above.
b)Positioned in the figure above so that each of A + B + C,C + D +E,E + F + G, and G + H + I is equal to 13.
Which digit does E represent?

Ans.E is 4
3.One of Mr. Horton,his wife,their son,and Mr. Horton's mother is a doctor and another is a lawyer.
a)If the doctor is younger than the lawyer, then the doctor and the lawyer are not blood relatives.
b)If the doctor is a woman, then the doctor and the lawyer are blood relatives.
c)If the lawyer is a man, then the doctor is a man.
Whose occupation you know?

Ans.Mr. Horton:he is the doctor.
4.Here is a picture of two cubes:

aztec.gif (1732 bytes)

a)The two cubes are exactly alike.
b)The hidden faces indicated by the dots have the same alphabet on them.
Which alphabet-q, r, w, or k is on the faces indicated by the dots?

Ans.q

5.In the following figure:
                                    A              D
                                    B      G     E
                                    C             F
Each of the seven digits from 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 is:
a)Represented by a different letter in the figure above.
b)Positioned in the figure above so that A*B*C,B*G*E, and D*E*F are equal.
Which digit does G represent?

Ans.G represents the digit 2.
6.Mr. and Mrs. Aye and Mr. and Mrs. Bee competed in a chess tournament.Of the three games played:
a)In only the first game werethe two players married to each other.
b)The men won two games and the women won one game.
c)The Ayes won more games than the Bees.
d)Anyone who lost game did not play the subsequent game.
Who did not lose a game?

Ans.Mrs.Bee did not lose a game.
7.Three piles of chips--pile I consists one chip, pile II consists of chips, and pile III consists of three chips--are to be used in game played by Anita and Brinda.The game requires:
a)That each player in turn take only one chip or all chips from just one pile.
b)That the player who has to take the last chip loses.
c)That Anita now have her turn.
From which pile should Anita draw in order to win?

Ans.Pile II

8.Of Abdul, Binoy, and Chandini:
a)Each member belongs to the Tee family whose members always tell the truth or to the El family whose members always lie.
b)Abdul says ''Either I belong or Binoy belongs to a different family from the other two."
Whose family do you name of?

Ans.Binoy's family--El.

9.In a class composed of x girls and y boys what part of the class is composed of girls

A.y/(x + y)
B.x/xy
C.x/(x + y)
D.y/xy

Ans.C

10.What is the maximum number of half-pint bottles of cream that can be filled with a 4-gallon can of cream(2 pt.=1 qt. and 4 qt.=1 gal)

A.16
B.24
C.30
D.64

Ans.D

11.If the operation,^ is defined by the equation x ^ y = 2x + y,what is the value of a in 2 ^ a = a ^ 3

A.0
B.1
C.-1
D.4

Ans.B

12.A coffee shop blends 2 kinds of coffee,putting in 2 parts of a 33p. a gm. grade to 1 part of a 24p. a gm.If the mixture is changed to 1 part of the 33p. a gm. to 2 parts of the less expensive grade,how much will the shop save in blending 100 gms.

A.Rs.90
B.Rs.1.00
C.Rs.3.00
D.Rs.8.00

Ans.C

13.There are 200 questions on a 3 hr examination.Among these questions are 50 mathematics problems.It is suggested that twice as much time be spent on each maths problem as for each other question.How many minutes should be spent on mathematics problems

A.36
B.72
C.60
D.100

Ans.B

14.In a group of 15,7 have studied Latin, 8 have studied Greek, and 3 have not studied either.How many of these studied both Latin and Greek

A.0
B.3
C.4
D.5

Ans.B

15.If 13 = 13w/(1-w) ,then (2w)²=

A.1/4
B.1/2
C.1
D.2

Ans.C

16. If a and b are positive integers and (a-b)/3.5 = 4/7, then
(A) b < a
(B) b > a
(C) b = a
(D) b >= a
Ans. A

17. In june a baseball team that played 60 games had won 30% of its game played. After a phenomenal winning streak this team raised its average to 50% .How many games must the team have won in a row to attain this average?
A. 12
B. 20
C. 24
D. 30
Ans. C

18. M men agree to purchase a gift for Rs. D. If three men drop out how much more will each have to contribute towards the purchase of the gift/
A. D/(M-3)
B. MD/3
C. M/(D-3)
D. 3D/(M²-3M)
Ans. D

19. A company contracts to paint 3 houses. Mr.Brown can paint a house in 6 days while Mr.Black would take 8 days and Mr.Blue 12 days. After 8 days Mr.Brown goes on vacation and Mr. Black begins to work for a period of 6 days. How many days will it take Mr.Blue to complete the contract?
A. 7
B. 8
C. 11
D. 12

Ans.C

20. 2 hours after a freight train leaves Delhi a passenger train leaves the same station travelling in the same direction at an average speed of 16 km/hr. After travelling 4 hrs the passenger train overtakes the freight train. The average speed of the freight train was?
A. 30
B. 40
C.58
D. 60
Ans. B

21. If 9x-3y=12 and 3x-5y=7 then 6x-2y = ?
A.-5
B. 4
C. 2
D. 8
Ans. D
22. There are 5 red shoes, 4 green shoes. If one draw randomly a shoe what is the probability of getting a red shoe

Ans 5c₁/ 9c₁

23. What is the selling price of a car? If the cost of the car is Rs.60 and a profit of 10% over selling price is earned

Ans: Rs 66/-

24. 1/3 of girls , 1/2 of boys go to canteen .What factor and total number of classmates go to canteen.

Ans: Cannot be determined.

25. The price of a product is reduced by 30% . By what percentage should it be increased to make it 100%

Ans: 42.857%

26. There is a square of side 6cm . A circle is inscribed inside the square. Find the ratio of the area of circle to square.
Ans. 11/14
27. There are two candles of equal lengths and of different thickness. The thicker one lasts of six hours. The thinner 2 hours less than the thicker one. Ramesh lights the two candles at the same time. When he went to bed he saw the thicker one is twice the length of the thinner one. How long ago did Ramesh light the two candles .

Ans: 3 hours.
28. If M/N = 6/5,then 3M+2N = ?
29. If p/q = 5/4 , then 2p+q= ?
30. If PQRST is a parallelogram what it the ratio of triangle PQS & parallelogram PQRST .
Ans: 1:2
31. The cost of an item is Rs 12.60. If the profit is 10% over selling price what is the selling price ?
Ans: Rs 13.86/-
32. There are 6 red shoes & 4 green shoes . If two of red shoes are drawn what is the probability of getting red shoes
Ans: 6c₂/10c₂
33. To 15 lts of water containing 20% alcohol, we add 5 lts of pure water. What is % alcohol.
Ans : 15%
34. A worker is paid Rs.20/- for a full days work. He works 1,1/3,2/3,1/8.3/4 days in a week. What is the total amount paid for that worker ?
Ans : 57.50
35. If the value of x lies between 0 & 1 which of the following is the largest?
(a) x
(b) x²
(c) -x
(d) 1/x

Ans : (d)
36. If the total distance of a journey is 120 km .If one goes by 60 kmph and comes back at 40kmph what is the average speed during the journey?
Ans: 48kmph
37. A school has 30% students from Maharashtra .Out of these 20% are Bombey students. Find the total percentage of Bombay?
Ans: 6%
38. An equilateral triangle of sides 3 inch each is given. How many equilateral triangles of side 1 inch can be formed from it?
Ans: 9
39. If A/B = 3/5,then 15A = ?
Ans : 9B
40. Each side of a rectangle is increased by 100% .By what percentage does the area increase?
Ans : 300%
41. Perimeter of the back wheel = 9 feet, front wheel = 7 feet on a certain distance, the front wheel gets 10 revolutions more than the back wheel .What is the distance?
Ans : 315 feet.
42. Perimeter of front wheel =30, back wheel = 20. If front wheel revolves 240 times. How many revolutions will the back wheel take?
Ans: 360 times
43. 20% of a 6 litre solution and 60% of 4 litre solution are mixed. What percentage of the mixture of solution
Ans: 36%
44City A's population is 68000, decreasing at a rate of 80 people per year. City B having population 42000 is increasing at a rate of 120 people per year. In how many years both the cities will have same population?
Ans: 130 years
45Two cars are 15 kms apart. One is turning at a speed of 50kmph and the other at 40kmph . How much time will it take for the two cars to meet?
Ans: 3/2 hours
46A person wants to buy 3 paise and 5 paise stamps costing exactly one rupee. If he buys which of the following number of stamps he won't able to buy 3 paise stamps.
Ans: 9
47There are 12 boys and 15 girls, How many different dancing groups can be formed with 2 boys and 3 girls.
48Which of the following fractions is less than 1/3
(a) 22/62
(b) 15/46
(c) 2/3
(d) 1
Ans: (b)
49There are two circles, one circle is inscribed and another circle is circumscribed over a square. What is the ratio of area of inner to outer circle?
Ans: 1 : 2
50Three types of tea the a,b,c costs Rs. 95/kg,100/kg and70/kg respectively.
     How many kgs of each should be blended to produce 100 kg of mixture worth Rs.90/kg,
     given that the quntities of band c are equal
a)70,15,15
b)50,25,25
c)60,20,20
d)40,30,30
Ans. (b)
51. in a class, except 18 all are above 50 years.
    15 are below 50 years of age. How many people are there
(a) 30
(b) 33
(c) 36
(d) none of these.
Ans. (d)
52. If a boat is moving in upstream with velocity of 14 km/hr and goes downstream with a velocity of 40 km/hr, then what is the speed of the stream ?

(a) 13 km/hr
(b) 26 km/hr
(c) 34 km/hr
(d) none of these
Ans. A
53. Find the value of ( 0.75 * 0.75 * 0.75 - 0.001 ) / ( 0.75 * 0.75 - 0.075 + 0.01)

(a) 0.845
(b) 1.908
(c) 2.312
(d) 0.001
Ans. A
54. A can have a piece of work done in 8 days, B can work three times faster than the A, C can work five times faster than A. How many days will they take to do the work together ?

(a) 3 days
(b) 8/9 days
(c) 4 days
(d) can't say
Ans. B
55. A car travels a certain distance taking 7 hrs in forward journey, during the return journey increased speed 12km/hr takes the times 5 hrs.What is the distance travelled

(a) 210 kms
(b) 30 kms
(c) 20 kms
(c) none of these
Ans. B
56. Instead of multiplying a number by 7, the number is divided by 7. What is the percentage of error obtained ?
57. Find (7x + 4y ) / (x-2y) if x/2y = 3/2 ?

(a) 6
(b) 8
(c) 7
(d) data insufficient
Ans. C
58. A man buys 12 lts of liquid which contains 20% of the liquid and the rest is water. He then mixes it with 10 lts of another mixture with 30% of liquid.What is the % of water in the new mixture?
59. If a man buys 1 lt of milk for Rs.12 and mixes it with 20% water and sells it for Rs.15, then what is the percentage of gain?
60. Pipe A can fill a tank in 30 mins and Pipe B can fill it in 28 mins.If 3/4th of the tank is filled by Pipe B alone and both are opened, how much time is required by both the pipes to fill the tank completely ?
61. If on an item a company gives 25% discount, they earn 25% profit. If they now give 10% discount then what is the profit percentage.
(a) 40%
(b) 55%
(c) 35%
(d) 30%
Ans. D
62. A certain number of men can finish a piece of work in 10 days. If however there were 10 men less it will take 10 days more for the work to be finished. How many men were there originally?

(a) 110 men
(b) 130 men
(c) 100 men
(d) none of these
Ans. A
63. In simple interest what sum amounts of Rs.1120/- in 4 years and Rs.1200/- in 5 years ?
(a) Rs. 500
(b) Rs. 600
(c) Rs. 800
(d) Rs. 900
Ans. C
64. If a sum of money compound annually amounts of thrice itself in 3 years. In how many years
will it become 9 times itself.

(a) 6
(b) 8
(c) 10
(d) 12
Ans A
65. Two trains move in the same direction at 50 kmph and 32 kmph respectively. A man in the slower train
observes the 15 seconds elapse before the faster train completely passes by him.
What is the length of faster train ?

(a) 100m
(b) 75m
(c) 120m
(d) 50m
Ans B
66. How many mashes are there in 1 squrare meter of wire gauge if each mesh
is 8mm long and 5mm wide ?

(a) 2500
(b) 25000
(c) 250
(d) 250000
Ans B
67. x% of y is y% of ?
(a) x/y
(b) 2y
(c) x
(d) can't be determined
Ans. C
68. The price of sugar increases by 20%, by what % should a housewife reduce the consumption of sugar so that expenditure on sugar can be same as before ?
(a) 15%
(b) 16.66%
(c) 12%
(d) 9%
Ans B
69. A man spends half of his salary on household expenses, 1/4th for rent, 1/5th for travel expenses, the man deposits the rest in a bank. If his monthly deposits in the bank amount 50, what is his monthly salary ?
(a) Rs.500
(b) Rs.1500
(c) Rs.1000
(d) Rs. 900
Ans C
70. The population of a city increases @ 4% p.a. There is an additional annual increase of 4% of the population due to the influx of job seekers, find the % increase in population after 2 years ?
71. The ratio of the number of boys and girls in a school is 3:2 Out of these 10% the boys and 25% of girls are scholarship holders. % of students who are not scholarship holders.?
72. 15 men take 21 days of 8 hrs. each to do a piece of work. How many days of 6 hrs. each would it take for 21 women if 3 women do as much work as 2 men?
(a) 30
(b) 20
(c) 19
(d) 29
Ans. A
73. A cylinder is 6 cms in diameter and 6 cms in height. If spheres of the same size are made from the material obtained, what is the diameter of each sphere?
(a) 5 cms
(b) 2 cms
(c) 3 cms
(d) 4 cms
Ans C
74. A rectangular plank (2)^1/2 meters wide can be placed so that it is on either side of the diagonal of a square shown below.(Figure is not available)What is the area of the plank?
Ans :7*(2)^1/2
75. The difference b/w the compound interest payble half yearly and the simple interest on a
certain sum lent out at 10% p.a for 1 year is Rs 25. What is the sum?
(a) Rs. 15000
(b) Rs. 12000
(c) Rs. 10000
(d) none of these
Ans C
76. What is the smallest number by which 2880 must be divided in order to make it into a
perfect square ?

(a) 3
(b) 4
(c) 5
(d) 6
Ans. C
77. A father is 30 years older than his son however he will be only thrice as old as the son after 5 years
what is father's present age ?

(a) 40 yrs
(b) 30 yrs
(c) 50 yrs
(d) none of these
Ans. A
78. An article sold at a profit of 20% if both the cost price and selling price would be Rs.20/- the profit would be 10% more. What is the cost price of that article?
29. If an item costs Rs.3 in '99 and Rs.203 in '00.What is the % increase in price?

(a) 200/3 %
(b) 200/6 %
(c) 100%
(d) none of these
Ans. A
80. 5 men or 8 women do equal amount of work in a day. a job requires 3 men and 5 women to finish the job in 10 days how many woman are required to finish the job in 14 days.

a) 10
b) 7
c) 6
d) 12
Ans 7
81. A simple interest amount of rs 5000 for six month is rs 200. what is the anual rate of interest?

a) 10%
b) 6%
c) 8%
d) 9%
Ans 8%
82. In objective test a correct ans score 4 marks and on a wrong ans 2 marks are ---. a student score 480 marks from       150 question. how many ans were correct?
a) 120
b) 130
c) 110
d) 150
Ans130.
83. An artical sold at amount of 50% the net sale price is rs 425 .what is the list price of the artical?

a) 500
b) 488
c) 480
d) 510
Ans 500
84. A man leaves office daily at 7pm A driver with car comes from his home to pick him from office and bring back home
     One day he gets free at 5:30 and instead of waiting for driver he starts walking towards home.
     In the way he meets the car and returns home on car He reaches home 20 minutes earlier than usual.
     In how much time does the man reach home usually??
Ans. 1hr 20min
85. A works thrice as much as B. If A takes 60 days less than B to do a work then find the number of days it would take to       complete the work if both work together?
Ans. 22½days
86. How many 1's are there in the binary form of 8*1024 + 3*64 + 3
Ans. 4
87. In a digital circuit which was to implement (A B) + (A)XOR(B), the designer implements (A B) (A)XOR(B)
    What is the probability of error in it ?
88. A boy has Rs 2. He wins or loses Re 1 at a time If he wins he gets Re 1 and if he loses the game he loses Re 1.
     He can loose only 5 times. He is out of the game if he earns Rs 5.
     Find the number of ways in which this is possible?
Ans. 16
89. If there are 1024*1280 pixels on a screen and each pixel can have around 16 million colors
     Find the memory required for this?
Ans. 4MB
90. On a particular day A and B decide that they would either speak the truth or will lie.
     C asks A whether he is speaking truth or lying?
     He answers and B listens to what he said. C then asks B what A has said B says "A says that he is a liar"
     What is B speaking ?
(a) Truth
(b) Lie
(c) Truth when A lies
(d) Cannot be determined
Ans. (b)
91. What is the angle between the two hands of a clock when time is 8:30
Ans. 75(approx)
92. A student is ranked 13th from right and 8th from left. How many students are there in totality ?
93. A man walks east and turns right and then from there to his left and then 45degrees to
his right.In which direction did he go

Ans. North west
94. A student gets 70% in one subject, 80% in the other. To get an overall of 75% how much should get in third subject.
95. A man shows his friend a woman sitting in a park and says that she the daughter of my  grandmother's only son.
    What is the relation between the two

Ans. Daughter

96. How many squares with sides 1/2 inch long are needed to cover a rectangle that is 4 ft long and 6 ft wide
(a) 24
(b) 96
(c) 3456
(d) 13824
(e) 14266
97. If a=2/3b , b=2/3c, and c=2/3d what part of d is b/
(a) 8/27
(b) 4/9
(c) 2/3
(d) 75%
(e) 4/3
Ans. (b)
2598Successive discounts of 20% and 15% are equal to a single discount of
(a) 30%
(b) 32%
(c) 34%
(d) 35%
(e) 36
Ans. (b)
99. The petrol tank of an automobile can hold g liters.If a liters was removed when the tank was full, what part of the full tank was removed?
(a)g-a
(b)g/a
(c) a/g
(d) (g-a)/a
(e) (g-a)/g
Ans. (c)

100. If x/y=4 and y is not '0' what % of x is 2x-y

(a)150%
(b)175%
(c)200%
(d)250%

Ans. (b)

Aptitude Questions Part-2

Aptitude Questions
1.If 2x-y=4 then 6x-3y=?
(a)15
(b)12
(c)18
(d)10

Ans. (b)
2.If x=y=2z and xyz=256 then what is the value of x?

(a)12
(b)8
(c)16
(d)6

Ans. (b)
3. (1/10)¹⁸ - (1/10)²⁰= ?
(a) 99/10²⁰(b) 99/10
(c) 0.9
(d) none of these
Ans. (a)
4.Pipe A can fill in 20 minutes and Pipe B in 30 mins and Pipe C can empty the same in 40 mins.If all of them work together, find the time taken to fill the tank
(a) 17 1/7 mins
(b) 20 mins
(c) 8 mins
(d) none of these
Ans. (a)
5. Thirty men take 20 days to complete a job working 9 hours a day.How many hour a day should 40 men work to complete the job?
(a) 8 hrs
(b) 7 1/2 hrs
(c) 7 hrs
(d) 9 hrs
Ans. (b)
6. Find the smallest number in a GP whose sum is 38 and product 1728
(a) 12
(b) 20
(c) 8
(d) none of these
Ans. (c)
7. A boat travels 20 kms upstream in 6 hrs and 18 kms downstream in 4 hrs.Find the speed of the boat in still water and the speed of the water current?
(a) 1/2 kmph
(b) 7/12 kmph
(c) 5 kmph
(d) none of these
Ans. (b)
8. A goat is tied to one corner of a square plot of side 12m by a rope 7m long.Find the area it can graze?
(a) 38.5 sq.m
(b) 155 sq.m
(c) 144 sq.m
(d) 19.25 sq.m
Ans. (a)
9. Mr. Shah decided to walk down the escalator of a tube station. He found that if he walks down 26 steps, he requires 30 seconds to reach the bottom. However, if he steps down 34 stairs he would only require 18 seconds to get to the bottom. If the time is measured from the moment the top step begins to descend to the time he steps off the last step at the bottom, find out the height of the stair way in steps?
Ans.46 steps.
10. The average age of 10 members of a committee is the same as it was 4 years ago, because an old member has been replaced by a young member. Find how much younger is the new member ?
Ans.40 years.
11. Three containers A, B and C have volumes a, b, and c respectively; and container A is full of water while the other two are empty. If from container A water is poured into container B which becomes 1/3 full, and into container C which becomes 1/2 full, how much water is left in container A?
12. ABCE is an isosceles trapezoid and ACDE is a rectangle. AB = 10 and EC = 20. What is the length of AE?
Ans. AE = 10.
13. In the given figure, PA and PB are tangents to the circle at A and B respectively and the chord BC is parallel to tangent PA. If AC = 6 cm, and length of the tangent AP is 9 cm, then what is the length of the chord BC?
Ans. BC = 4 cm.
15 Three cards are drawn at random from an ordinary pack of cards. Find the probability that they will consist of a king, a queen and an ace.
Ans. 64/2210.
16. A number of cats got together and decided to kill between them 999919 mice. Every cat killed an equal number of mice. Each cat killed more mice than there were cats. How many cats do you think there were ?
Ans. 991.
17. If Log2 x - 5 Log x + 6 = 0, then what would the value / values of x be?
Ans. x = e2 or e3.
18. The square of a two digit number is divided by half the number. After 36 is added to the quotient, this sum is then divided by 2. The digits of the resulting number are the same as those in the original number, but they are in reverse order. The ten's place of the original number is equal to twice the difference between its digits. What is the number?
Ans. 46
19.Can you tender a one rupee note in such a manner that there shall be total 50 coins but none of them would be 2 paise coins.?
Ans. 45 one paisa coins, 2 five paise coins, 2 ten paise coins, and 1 twenty-five paise coins.
20.A monkey starts climbing up a tree 20ft. tall. Each hour, it hops 3ft. and slips back 2ft. How much time would it take the monkey to reach the top?
Ans.18 hours.
21. What is the missing number in this series? 8 2 14 6 11 ? 14 6 18 12
Ans. 9
22. A certain type of mixture is prepared by mixing brand A at Rs.9 a kg. with brand B at Rs.4 a kg. If the mixture is worth Rs.7 a kg., how many kgs. of brand A are needed to make 40kgs. of the mixture?
Ans. Brand A needed is 24kgs.
23. A wizard named Nepo says "I am only three times my son's age. My father is 40 years more than twice my age. Together the three of us are a mere 1240 years old." How old is Nepo?
Ans. 360 years old.
24. One dog tells the other that there are two dogs in front of me. The other one also shouts that he too had two behind him. How many are they?
Ans. Three.
25. A man ate 100 bananas in five days, each day eating 6 more than the previous day. How many bananas did he eat on the first day?
Ans. Eight.
26. If it takes five minutes to boil one egg, how long will it take to boil four eggs?
Ans. Five minutes.
27. The minute hand of a clock overtakes the hour hand at intervals of 64 minutes of correct time. How much a day does the clock gain or lose?
Ans. 32 8/11 minutes.
28. Solve for x and y: 1/x - 1/y = 1/3, 1/x2 + 1/y2 = 5/9.
Ans. x = 3/2 or -3 and y = 3 or -3/2.
29. Daal is now being sold at Rs. 20 a kg. During last month its rate was Rs. 16 per kg. By how much percent should a family reduce its consumption so as to keep the expenditure fixed?
Ans. 20 %.
30. Find the least value of 3x + 4y if x2y3 = 6.
Ans. 10.
31. Can you find out what day of the week was January 12, 1979?
Ans. Friday.
32. A garrison of 3300 men has provisions for 32 days, when given at a rate of 850 grams per head. At the end of 7 days a reinforcement arrives and it was found that now the provisions will last 8 days less, when given at the rate of 825 grams per head. How, many more men can it feed?
Ans. 1700 men.
33. From 5 different green balls, four different blue balls and three different red balls, how many combinations of balls can be chosen taking at least one green and one blue ball?
Ans. 3720.
34. Three pipes, A, B, & C are attached to a tank. A & B can fill it in 20 & 30 minutes respectively while C can empty it in 15 minutes. If A, B & C are kept open successively for 1 minute each, how soon will the tank be filled?
Ans. 167 minutes.
35. A person walking 5/6 of his usual rate is 40 minutes late. What is his usual time? Ans. 3 hours 20 minutes.

36.For a motorist there are three ways going from City A to City C. By way of bridge the distance is 20 miles and toll is $0.75. A tunnel between the two cities is a distance of 10 miles and toll is $1.00 for the vehicle and driver and $0.10 for each passenger. A two-lane highway without toll goes east for 30 miles to city B and then 20 miles in a northwest direction to City C.

1. Which is the shortest route from B to C

(a) Directly on toll free highway to City C
(b) The bridge
(c) The Tunnel
(d) The bridge or the tunnel
(e) The bridge only if traffic is heavy on the toll free highway

Ans. (a)

2. The most economical way of going from City A to City B, in terms of toll and distance is to use the

(a) tunnel
(b) bridge
(c) bridge or tunnel
(d) toll free highway
(e) bridge and highway

Ans. (a)

3. Jim usually drives alone from City C to City A every working day. His firm deducts a percentage of employee pay for lateness. Which factor would most influence his choice of the bridge or the tunnel ?

(a) Whether his wife goes with him
(b) scenic beauty on the route
(c) Traffic conditions on the road, bridge and tunnel
(d) saving $0.25 in tolls
(e) price of gasoline consumed in covering additional 10 miles on the bridge

Ans. (a)

4. In choosing between the use of the bridge and the tunnel the chief factor(s) would be:
I. Traffic and road conditions
II. Number of passengers in the car
III. Location of one's homes in the center or outskirts of one of the cities
IV. Desire to save $0.25

(a) I only
(b) II only
(c) II and III only
(d) III and IV only
(e) I and II only

Ans. (a)

37.The letters A, B, C, D, E, F and G, not necessarily in that order, stand for seven consecutive integers from 1 to 10
D is 3 less than A
B is the middle term
F is as much less than B as C is greater than D
G is greater than F

1. The fifth integer is
(a) A
(b) C
(c) D
(d) E
(e) F

Ans. (a)

2. A is as much greater than F as which integer is less than G
(a) A
(b) B
(c) C
(d) D
(e) E

Ans. (a)

3. If A = 7, the sum of E and G is
(a) 8
(b) 10
(c) 12
(d) 14
(e) 16

Ans. (a)

4. A - F = ?
(a) 1
(b) 2
(c) 3
(d) 4
(e) Cannot be determined

Ans. (a)

5. An integer T is as much greater than C as C is greater than E. T can be written as A + E. What is D?
(a) 2
(b) 3
(c) 4
(d) 5
(e) Cannot be determined

Ans. (a)

6. The greatest possible value of C is how much greater than the smallest possible value of D?
(a) 2
(b) 3
(c) 4
(d) 5
(e) 6

Ans. (a)

38.
1. All G's are H's
2. All G's are J's or K's
3. All J's and K's are G's
4. All L's are K's
5. All N's are M's
6. No M's are G's

1. If no P's are K's, which of the following must be true?

(a) All P's are J's
(b) No P is a G
(c) No P is an H
(d) If any P is an H it is a G
(e) If any P is a G it is a J

Ans. (a)

2. Which of the following can be logically deduced from the conditions stated?

(a) No M's are H's
(b) No M's that are not N's are H's
(c) No H's are M's
(d) Some M's are H's
(e) All M's are H's

Ans. (a)

3. Which of the following is inconsistent with one or more of the conditions?

(a) All H's are G's
(b) All H's that are not G's are M's
(c) Some H's are both M's and G's
(d) No M's are H's
(e) All M's are H's

Ans. (a)

4. The statement "No L's are J's" is
I. Logically deducible from the conditions stated
II. Consistent with but not deducible from the conditions stated
III. Deducible from the stated conditions together with the additional statement "No J's are K's"

(a) I only
(b) II only
(c) III only
(d) II and III only
(e) Neither I, II nor III

Ans. (a)

39.In country X, democratic, conservative and justice parties have fought three civil wars in twenty years. TO restore stability an agreement is reached to rotate the top offices President, Prime Minister and Army Chief among the parties so that each party controls one and only one office at all times. The three top office holders must each have two deputies, one from each of the other parties. Each deputy must choose a staff composed of equally members of his or her chiefs party and member of the third party.

1. When Justice party holds one of the top offices, which of the following cannot be true

(a) Some of the staff members within that office are justice party members
(b) Some of the staff members within that office are democratic party members
(c) Two of the deputies within the other offices are justice party members
(d) Two of the deputies within the other offices are conservative party members
(e) Some of the staff members within the other offices are justice party members.

Ans. (a)

2. When the democratic party holds presidency, the staff of the prime minister's deputies are composed
I. One-fourth of democratic party members
II. One-half of justice party members and one-fourth of conservative party members
III. One-half of conservative party members and one-fourth of justice party members.

(a) I only
(b) I and II only
(c) II or III but not both
(d) I and II or I and III
(e) None of these

Ans. (a)

3. Which of the following is allowable under the rules as stated:

(a) More than half of the staff within a given office belonging to a single party
(b) Half of the staff within a given office belonging to a single party
(c) Any person having a member of the same party as his or her immediate superior
(d) Half the total number of staff members in all three offices belonging to a single party
(e) Half the staff members in a given office belonging to parties different from the party of the top office holder in that office.

Ans. (a)

4. The office of the Army Chief passes from Conservative to Justice party. Which of the following must be fired.

(a) The democratic deputy and all staff members belonging to Justice party
(b) Justice party deputy and all his or hers staff members
(c) Justice party deputy and half of his Conservative staff members in the chief of staff office
(d) The Conservative deputy and all of his or her staff members belonging to Conservative party
(e) No deputies and all staff members belonging to conservative parties.

Ans. (a)

40.In recommendations to the board of trustees a tuition increase of $500 per year, the president of the university said "There were no student demonstrations over the previous increases of $300 last year and $200 the year before". If the president's statement is accurate then which of the following can be validly inferred from the information given:
I. Most students in previous years felt that the increases were justified because of increased operating costs.
II. Student apathy was responsible for the failure of students to protest the previous tuition increases.
III. Students are not likely to demonstrate over new tuition increases.

(a) I only
(b) II only
(c) I or II but not both
(d) I, II and III
(e) None

Ans. (a)

41. The office staff of XYZ corporation presently consists of three bookeepers--A, B, C and 5 secretaries D, E, F, G, H. The management is planning to open a new office in another city using 2 bookeepers and 3 secretaries of the present staff . To do so they plan to seperate certain individuals who don't function well together. The following guidelines were established to set up the new office
I. Bookeepers A and C are constantly finding fault with one another and should not be sent together to the new office as a team
II. C and E function well alone but not as a team , they should be seperated
III. D and G have not been on speaking terms and shouldn't go together
IV Since D and F have been competing for promotion they shouldn't be a team
1.If A is to be moved as one of the bookeepers,which of the following cannot be a possible working unit.

A.ABDEH
B.ABDGH
C.ABEFH
D.ABEGH

Ans.B

2.If C and F are moved to the new office,how many combinations are possible

A.1
B.2
C.3
D.4

Ans.A

3.If C is sent to the new office,which member of the staff cannot go with C

A.B
B.D
C.F
D.G

Ans.B

4.Under the guidelines developed,which of the following must go to the new office

A.B
B.D
C.E
D.G

Ans.A

5.If D goes to the new office,which of the following is/are true

I.C cannot go
II.A cannot go
III.H must also go

A.I only
B.II only
C.I and II only
D.I and III only

Ans.D

42.After months of talent searching for an administrative assistant to the president of the college the field of applicants has been narrowed down to 5--A, B, C, D, E .It was announced that the finalist would be chosen after a series of all-day group personal interviews were held.The examining committee agreed upon the following procedure

I.The interviews will be held once a week
II.3 candidates will appear at any all-day interview session
III.Each candidate will appear at least once
IV.If it becomes necessary to call applicants for additonal interviews, no more 1 such applicant should be asked to appear the next week
V.Because of a detail in the written applications,it was agreed that whenever candidate B appears, A should also be present.
VI.Because of travel difficulties it was agreed that C will appear for only 1 interview.
1.At the first interview the following candidates appear A,B,D.Which of the follwing combinations can be called for the interview to be held next week.

A.BCD
B.CDE
C.ABE
D.ABC

Ans.B

2.Which of the following is a possible sequence of combinations for interviews in 2 successive weeks

A.ABC;BDE
B.ABD;ABE
C.ADE;ABC
D.BDE;ACD

Ans.C

3.If A ,B and D appear for the interview and D is called for additional interview the following week,which 2 candidates may be asked to appear with D?

I. A
II B
III.C
IV.E
A.I and II
B.I and III only
C.II and III only
D.III and IV only

Ans.D

4.Which of the following correctly state(s) the procedure followed by the search committee

I.After the second interview all applicants have appeared at least once
II.The committee sees each applicant a second time
III.If a third session,it is possible for all applicants to appear at least twice

A.I only
B.II only
C.III only
D.Both I and II

Ans.A

43. A certain city is served by subway lines A,B and C and numbers 1 2 and 3
When it snows , morning service on B is delayed
When it rains or snows , service on A, 2 and 3 are delayed both in the morning and afternoon
When temp. falls below 30 degrees farenheit afternoon service is cancelled in either the A line or the 3 line,
but not both.
When the temperature rises over 90 degrees farenheit, the afternoon service is cancelled in either the line C or the
3 line but not both.
When the service on the A line is delayed or cancelled, service on the C line which connects the A line, is delayed.
When service on the 3 line is cancelled, service on the B line which connects the 3 line is delayed.
Q1. On Jan 10th, with the temperature at 15 degree farenheit, it snows all day. On how many lines will service be
affected, including both morning and afternoon.
(A) 2
(B) 3
(C) 4
(D) 5
Ans. D

Q2. On Aug 15th with the temperature at 97 degrees farenheit it begins to rain at 1 PM. What is the minimum number
of lines on which service will be affected?
(A) 2
(B) 3
(C) 4
(D) 5
Ans. C

Q3. On which of the following occasions would service be on the greatest number of lines disrupted.
(A) A snowy afternoon with the temperature at 45 degree farenheit
(B) A snowy morning with the temperature at 45 degree farenheit
(C) A rainy afternoon with the temperature at 45 degree farenheit
(D) A rainy afternoon with the temperature at 95 degree farenheit
Ans. B

44. In a certain society, there are two marriage groups, red and brown. No marriage is permitted within a group. On marriage, males become part of their wives groups; women remain in their own group. Children belong to the same group as their parents. Widowers and divorced males revert to the group of their birth. Marriage to more than one person at the same time and marriage to a direct descendant are forbidden
Q1. A brown female could have had
I. A grandfather born Red
II. A grandmother born Red
III Two grandfathers born Brown
(A) I only
(B) III only
(C) I, II and III
(D) I and II only
Ans. D

Q2. A male born into the brown group may have
(A) An uncle in either group
(B) A brown daughter
(C) A brown son
(D) A son-in-law born into red group
Ans. A

Q3. Which of the following is not permitted under the rules as stated.
(A) A brown male marrying his father's sister
(B) A red female marrying her mother's brother
(C) A widower marrying his wife's sister
(D) A widow marrying her divorced daughter's ex-husband
Ans. B

Q4. If widowers and divorced males retained their group they had upon marrying which of the following would be permissible ( Assume that no previous marriage occurred)
(A) A woman marrying her dead sister's husband
(B) A woman marrying her divorced daughter's ex-husband
(C) A widower marrying his brother's daughter
(D) A woman marrying her mother's brother who is a widower.
Ans. D

Q5. I. All G's are H's
II. All G's are J's or K's
III All J's and K's are G's
IV All L's are K's
V All N's are M's
VI No M's are G's
45. There are six steps that lead from the first to the second floor. No two people can be on the same step
Mr. A is two steps below Mr. C
Mr. B is a step next to Mr. D
Only one step is vacant ( No one standing on that step )
Denote the first step by step 1 and second step by step 2 etc.
1. If Mr. A is on the first step, Which of the following is true?
(a) Mr. B is on the second step
(b) Mr. C is on the fourth step.
(c) A person Mr. E, could be on the third step
(d) Mr. D is on higher step than Mr. C.
Ans: (d)
2. If Mr. E was on the third step & Mr. B was on a higher step than Mr. E which step must be vacant
(a) step 1
(b) step 2
(c) step 4
(d) step 5
(e) step 6
Ans: (a)
3. If Mr. B was on step 1, which step could A be on?
(a) 2&e only
(b) 3&5 only
(c) 3&4 only
(d) 4&5 only
(e) 2&4 only
Ans: (c)
4. If there were two steps between the step that A was standing and the step that B was standing on, and A was on a higher step than D , A must be on step
(a) 2
(b) 3
(c) 4
(d) 5
(e) 6
Ans: (c)

5. Which of the following is false

i. B&D can be both on odd-numbered steps in one configuration
ii. In a particular configuration A and C must either both an odd numbered steps or both an even-numbered steps
iii. A person E can be on a step next to the vacant step.
(a) i only
(b) ii only
(c) iii only
(d) both i and iii
Ans: (c)

46. Six swimmers A, B, C, D, E, F compete in a race. The outcome is as follows.
i. B does not win.
ii. Only two swimmers separate E & D
iii. A is behind D & E
iv. B is ahead of E , with one swimmer intervening
v. F is a head of D
1. Who stood fifth in the race ?
(a) A
(b) B
(c) C
(d) D
(e) E
Ans: (e)
2. How many swimmers seperate A and F ?
(a) 1
(b) 2
(c) 3
(d) 4
(e) cannot be determined
Ans: (d)
3. The swimmer between C & E is
(a) none
(b) F
(c) D
(d) B
(e) A
Ans: (a)

4. If the end of the race, swimmer D is disqualified by the Judges then swimmer B finishes in which place
(a) 1
(b) 2
(c) 3
(d) 4
(e) 5
Ans: (b)
47. Five houses lettered A,B,C,D, & E are built in a row next to each other. The houses are lined up in the order A,B,C,D, & E. Each of the five houses has a colored chimney. The roof and chimney of each housemust be painted as follows.
i. The roof must be painted either green,red ,or yellow.
ii. The chimney must be painted either white, black, or red.
iii. No house may have the same color chimney as the color of roof.
iv. No house may use any of the same colors that the every next house uses.
v. House E has a green roof.
vi. House B has a red roof and a black chimney
1. Which of the following is true ?
(a) At least two houses have black chimney.
(b) At least two houses have red roofs.
(c) At least two houses have white chimneys
(d) At least two houses have green roofs
(e) At least two houses have yellow roofs
Ans: (c)
2. Which must be false ?
(a) House A has a yellow roof
(b) House A & C have different color chimney
(c) House D has a black chimney
(d) House E has a white chimney
(e) House B&D have the same color roof.
Ans: (b)
3. If house C has a yellow roof. Which must be true.
(a) House E has a white chimney
(b) House E has a black chimney
(c) House E has a red chimney
(d) House D has a red chimney
(e) House C has a black chimney
Ans: (a)
4. Which possible combinations of roof & chimney can house
I. A red roof 7 a black chimney
II. A yellow roof & a red chimney
III. A yellow roof & a black chimney

(a) I only
(b) II only
(c) III only
(d) I & II only
(e) I&II&III
Ans: (e)

48. Find x+2y
(i). x+y=10
(ii). 2x+4y=20
Ans: (b)

49. Is angle BAC is a right angle
(i) AB=2BC
(2) BC=1.5AC
Ans: (e)
50. Is x greater than y
(i) x=2k
(ii) k=2y
Ans: (e)

Aptitude Part-3

Aptitude Questions

Solve the following and check with the answers given at the end.

1. It was calculated that 75 men could complete a piece of work in 20 days. When work was scheduled to commence, it was found necessary to send 25 men to another project. How much longer will it take to complete the work?

2. A student divided a number by 2/3 when he required to multiply by 3/2. Calculate the percentage of error in his result.

3. A dishonest shopkeeper professes to sell pulses at the cost price, but he uses a false weight of 950gm. for a kg. His gain is …%.

4. A software engineer has the capability of thinking 100 lines of code in five minutes and can type 100 lines of code in 10 minutes. He takes a break for five minutes after every ten minutes. How many lines of codes will he complete typing after an hour?

5. A man was engaged on a job for 30 days on the condition that he would get a wage of Rs. 10 for the day he works, but he have to pay a fine of Rs. 2 for each day of his absence. If he gets Rs. 216 at the end, he was absent for work for ... days.

6. A contractor agreeing to finish a work in 150 days, employed 75 men each working 8 hours daily. After 90 days, only 2/7 of the work was completed. Increasing the number of men by ________ each working now for 10 hours daily, the work can be completed in time.

7. what is a percent of b divided by b percent of a?

(a) a (b) b (c) 1 (d) 10 (d) 100

8. A man bought a horse and a cart. If he sold the horse at 10 % loss and the cart at 20 % gain, he would not lose anything; but if he sold the horse at 5% loss and the cart at 5% gain, he would lose Rs. 10 in the bargain. The amount paid by him was Rs._______ for the horse and Rs.________ for the cart.

9. A tennis marker is trying to put together a team of four players for a tennis tournament out of seven available. males - a, b and c; females – m, n, o and p. All players are of equal ability and there must be at least two males in the team. For a team of four, all players must be able to play with each other under the following restrictions:

b should not play with m,

c should not play with p, and

a should not play with o.

Which of the following statements must be false?

1. b and p cannot be selected together

2. c and o cannot be selected together

3. c and n cannot be selected together.

10-12. The following figure depicts three views of a cube. Based on this, answer questions 10-12.

6 5 Cube: 2

1 22 3 6

10. The number on the face opposite to the face carrying 1 is _______ .

11. The number on the faces adjacent to the face marked 5 are _______ .

12. Which of the following pairs does not correctly give the numbers on the opposite faces.

(1) 6,5 (2) 4,1 (3) 1,3 (4) 4,2

13. Five farmers have 7, 9, 11, 13 & 14 apple trees, respectively in their orchards. Last year, each of them discovered that every tree in their own orchard bore exactly the same number of apples. Further, if the third farmer gives one apple to the first, and the fifth gives three to each of the second and the fourth, they would all have exactly the same number of apples. What were the yields per tree in the orchards of the third and fourth farmers?

14. Five boys were climbing a hill. J was following H. R was just ahead of G. K was between G & H. They were climbing up in a column. Who was the second?

15-18 John is undecided which of the four novels to buy. He is considering a spy

thriller, a Murder mystery, a Gothic romance and a science fiction novel. The books are written by Rothko, Gorky, Burchfield and Hopper, not necessary in that order, and published by Heron, Piegon, Blueja and sparrow, not necessary in that order.

(1) The book by Rothko is published by Sparrow.

(2) The Spy thriller is published by Heron.

(3) The science fiction novel is by Burchfield and is not published by Blueja.

(4)The Gothic romance is by Hopper.

15. Pigeon publishes ____________.

16. The novel by Gorky ________________.

17. John purchases books by the authors whose names come first and third in alphabetical order. He does not buy the books ______.

18. On the basis of the first paragraph and statement (2), (3) and (4) only, it is possible to deduce that

1. Rothko wrote the murder mystery or the spy thriller

2. Sparrow published the murder mystery or the spy thriller

3. The book by Burchfield is published by Sparrow.

19. If a light flashes every 6 seconds, how many times will it flash in ¾ of an hour?

20. If point P is on line segment AB, then which of the following is always true?

(1) AP = PB (2) AP > PB (3) PB > AP (4) AB > AP (5) AB > AP + PB

21. All men are vertebrates. Some mammals are vertebrates. Which of the following conclusions drawn from the above statement is correct.

All men are mammals

All mammals are men

Some vertebrates are mammals.

None

22. Which of the following statements drawn from the given statements are correct?

Given:

All watches sold in that shop are of high standard. Some of the HMT watches are sold in that shop.

a) All watches of high standard were manufactured by HMT.

b) Some of the HMT watches are of high standard.

c) None of the HMT watches is of high standard.

d) Some of the HMT watches of high standard are sold in that shop.

23-27.

1. Ashland is north of East Liverpool and west of Coshocton.

2. Bowling green is north of Ashland and west of Fredericktown.

3. Dover is south and east of Ashland.

4. East Liverpool is north of Fredericktown and east of Dover.

5. Fredericktown is north of Dover and west of Ashland.

6. Coshocton is south of Fredericktown and west of Dover.

23. Which of the towns mentioned is furthest of the north – west

(a) Ashland (b) Bowling green (c) Coshocton

(d) East Liverpool (e) Fredericktown

24. Which of the following must be both north and east of Fredericktown?

(a) Ashland (b) Coshocton (c) East Liverpool

I a only II b only III c only IV a & b V a & c

25. Which of the following towns must be situated both south and west of at least one other town?

A. Ashland only

B. Ashland and Fredericktown

C. Dover and Fredericktown

D. Dover, Coshocton and Fredericktown

E. Coshocton, Dover and East Liverpool.

26. Which of the following statements, if true, would make the information in the numbered statements more specific?

(a) Coshocton is north of Dover.

(b) East Liverpool is north of Dover

(d) Coshocton is east of Fredericktown

(e) Bowling green is north of Fredericktown

27. Which of the numbered statements gives information that can be deduced from one or more of the other statements?

(A) 1 (B) 2 (C) 3 (D) 4 (E) 6

28. Eight friends Harsha, Fakis, Balaji, Eswar, Dhinesh, Chandra, Geetha, and Ahmed are sitting in a circle facing the center. Balaji is sitting between Geetha and Dhinesh. Harsha is third to the left of Balaji and second to the right of Ahmed. Chandra is sitting between Ahmed and Geetha and Balaji and Eshwar are not sitting opposite to each other. Who is third to the left of Dhinesh?

29. If every alternative letter starting from B of the English alphabet is written in small letter, rest all are written in capital letters, how the month “ September” be written.

(1) SeptEMbEr (2) SEpTeMBEr (3) SeptembeR

(4) SepteMber (5) None of the above.

30. The length of the side of a square is represented by x+2. The length of the side of an equilateral triangle is 2x. If the square and the equilateral triangle have equal perimeter, then the value of x is _______.

31. It takes Mr. Karthik y hours to complete typing a manuscript. After 2 hours, he was called away. What fractional part of the assignment was left incomplete?

32. Which of the following is larger than 3/5?

(1) ½ (2) 39/50 (3) 7/25 (4) 3/10 (5) 59/100

33. The number that does not have a reciprocal is ____________.

34. There are 3 persons Sudhir, Arvind, and Gauri. Sudhir lent cars to Arvind and Gauri as many as they had already. After some time Arvind gave as many cars to Sudhir and Gauri as many as they have. After sometime Gauri did the same thing. At the end of this transaction each one of them had 24. Find the cars each originally had.

35. A man bought a horse and a cart. If he sold the horse at 10 % loss and the cart at 20 % gain, he would not lose anything; but if he sold the horse at 5% loss and the cart at 5% gain, he would lose Rs. 10 in the bargain. The amount paid by him was Rs._______ for the horse and Rs.________ for the cart.

Answers:

1. Answer:

30 days.

Explanation:

Before:

One day work = 1 / 20

One man’s one day work = 1 / ( 20 * 75)

Now:

No. Of workers = 50

One day work = 50 * 1 / ( 20 * 75)

The total no. of days required to complete the work = (75 * 20) / 50 = 30

2. Answer:

0 %

Explanation:

Since 3x / 2 = x / (2 / 3)

3. Answer:

5.3 %

Explanation:

He sells 950 grams of pulses and gains 50 grams.

If he sells 100 grams of pulses then he will gain (50 / 950) *100 = 5.26

4. Answer:

250 lines of codes

5. Answer:

7 days

Explanation:

The equation portraying the given problem is:

10 * x – 2 * (30 – x) = 216 where x is the number of working days.

Solving this we get x = 23

Number of days he was absent was 7 (30-23) days.

6. Answer:

150 men.

Explanation:

One day’s work = 2 / (7 * 90)

One hour’s work = 2 / (7 * 90 * 8)

One man’s work = 2 / (7 * 90 * 8 * 75)

The remaining work (5/7) has to be completed within 60 days, because the total number of days allotted for the project is 150 days.

So we get the equation

(2 * 10 * x * 60) / (7 * 90 * 8 * 75) = 5/7 where x is the number of men working after the 90^th day.

We get x = 225

Since we have 75 men already, it is enough to add only 150 men.

7. Answer:

Explanation:

a percent of b : (a/100) * b

b percent of a : (b/100) * a

a percent of b divided by b percent of a : ((a / 100 )*b) / (b/100) * a )) = 1

8. Answer:

Cost price of horse = Rs. 400 & the cost price of cart = 200.

Explanation:-

Let x be the cost price of the horse and y be the cost price of the cart.

In the first sale there is no loss or profit. (i.e.) The loss obtained is equal to the gain.

Therefore (10/100) * x = (20/100) * y

X = 2 * y -----------------(1)

In the second sale, he lost Rs. 10. (i.e.) The loss is greater than the profit by Rs. 10.

Therefore (5 / 100) * x = (5 / 100) * y + 10 -------(2)

Substituting (1) in (2) we get

(10 / 100) * y = (5 / 100) * y + 10

(5 / 100) * y = 10

y = 200

From (1) 2 * 200 = x = 400

9. Answer:

Explanation:

Since inclusion of any male player will reject a female from the team. Since there should be four member in the team and only three males are available, the girl, n should included in the team always irrespective of others selection.

10. Answer:

11. Answer:

1,2,3 & 4

12. Answer:

13. Answer:

11 & 9 apples per tree.

Explanation:

Let a, b, c, d & e be the total number of apples bored per year in A, B, C, D & E ‘s orchard. Given that a + 1 = b + 3 = c – 1 = d + 3 = e – 6

But the question is to find the number of apples bored per tree in C and D ‘s orchard. If is enough to consider c – 1 = d + 3.

Since the number of trees in C’s orchard is 11 and that of D’s orchard is 13. Let x and y be the number of apples bored per tree in C & d ‘s orchard respectively.

Therefore 11 x – 1 = 13 y + 3

By trial and error method, we get the value for x and y as 11 and 9

14. Answer:

Explanation:

The order in which they are climbing is R – G – K – H – J

15 – 18

Answer:

Novel Name Author Publisher

Spy thriller Rathko Heron

Murder mystery Gorky Piegon

Gothic romance Burchfield Blueja

Science fiction Hopper Sparrow

Explanation:

Given

Novel Name Author Publisher

Spy thriller Rathko Heron

Murder mystery Gorky Piegon

Gothic romance Burchfield Blueja

Science fiction Hopper Sparrow

Since Blueja doesn’t publish the novel by Burchfield and Heron publishes the novel spy thriller, Piegon publishes the novel by Burchfield.

Since Hopper writes Gothic romance and Heron publishes the novel spy thriller, Blueja publishes the novel by Hopper.

Since Heron publishes the novel spy thriller and Heron publishes the novel by Gorky, Gorky writes Spy thriller and Rathko writes Murder mystery.

19. Answer:

451 times.

Explanation:

There are 60 minutes in an hour.

In ¾ of an hour there are (60 * ¾) minutes = 45 minutes.

In ¾ of an hour there are (60 * 45) seconds = 2700 seconds.

Light flashed for every 6 seconds.

In 2700 seconds 2700/6 = 450 times.

The count start after the first flash, the light will flashes 451 times in ¾ of an hour.

20. Answer:

(4)

Explanation:

A B

Since p is a point on the line segment AB, AB > AP

21. Answer: (c)

22. Answer: (b) & (d).

Ahmed

23 - 27.Answer:

Fakis Chandra

28. Answer: Fakis

Explanation: Harsha Geetha

Eswar Balaji

Dhinesh

29. Answer:

(5).

Explanation:

Since every alternative letter starting from B of the English alphabet is written in small letter, the letters written in small letter are b, d, f...

In the first two answers the letter E is written in both small & capital letters, so they are not the correct answers. But in third and fourth answers the letter is written in small letter instead capital letter, so they are not the answers.

30. Answer:

x = 4

Explanation:

Since the side of the square is x + 2, its perimeter = 4 (x + 2) = 4x + 8

Since the side of the equilateral triangle is 2x, its perimeter = 3 * 2x = 6x

Also, the perimeters of both are equal.

(i.e.) 4x + 8 = 6x

(i.e.) 2x = 8 è x = 4.

31. Answer:

(y – 2) / y.

Explanation:

To type a manuscript karthik took y hours.

Therefore his speed in typing = 1/y.

He was called away after 2 hours of typing.

Therefore the work completed = 1/y * 2.

Therefore the remaining work to be completed = 1 – 2/y.

(i.e.) work to be completed = (y-2)/y

32. Answer:

(2)

33. Answer:

Explanation:

One is the only number exists without reciprocal because the reciprocal of one is one itself.

34. Answer:

Sudhir had 39 cars, Arvind had 21 cars and Gauri had 12 cars.

Explanation:

Sudhir Arvind Gauri

Finally 24 24 24

Before Gauri’s transaction 12 12 48

Before Arvind’s transaction 6 42 24

Before Sudhir’ s transaction 39 21 12

35. Answer:

Cost price of horse: Rs. 400 &

Cost price of cart: Rs. 200

Explanation:

Let x be the cost of horse & y be the cost of the cart.

10 % of loss in selling horse = 20 % of gain in selling the cart

Therefore (10 / 100) * x = (20 * 100) * y

è x = 2y -----------(1)

5 % of loss in selling the horse is 10 more than the 5 % gain in selling the cart.

Therefore (5 / 100) * x - 10 = (5 / 100) * y

è 5x - 1000 = 5y

Substituting (1)

10y - 1000 = 5y

5y = 1000

y = 200

x = 400 from (1)

Exercise 2.1

For the following, find the next term in the series

1. 6, 24, 60,120, 210

a) 336 b) 366 c) 330 d) 660

Answer : a) 336

Explanation : The series is 1.2.3, 2.3.4, 3.4.5, 4.5.6, 5.6.7, ..... ( '.' means product)

2. 1, 5, 13, 25

Answer : 41

Explanation : The series is of the form 0^2+1^2, 1^2+2^2,...

3. 0, 5, 8, 17

Answer : 24

Explanation : 1^2-1, 2^2+1, 3^2-1, 4^2+1, 5^2-1

4. 1, 8, 9, 64, 25 (Hint : Every successive terms are related)

Answer : 216

Explanation : 1^2, 2^3, 3^2, 4^3, 5^2, 6^3

5. 8,24,12,36,18,54

Answer : 27

6. 71,76,69,74,67,72

Answer : 67

7. 5,9,16,29,54

Answer : 103

Explanation : 5*2-1=9; 9*2-2=16; 16*2-3=29; 29*2-4=54; 54*2-5=103

8. 1,2,4,10,16,40,64 (Successive terms are related)

Answer : 200

Explanation : The series is powers of 2 (2^0,2^1,..).

All digits are less than 8. Every second number is in octal number system.

128 should follow 64. 128 base 10 = 200 base 8.

Exercise 2.2

Find the odd man out.

1. 3,5,7,12,13,17,19

Answer : 12

Explanation : All but 12 are odd numbers

2. 2,5,10,17,26,37,50,64

Answer : 64

Explanation : 2+3=5; 5+5=10; 10+7=17; 17+9=26; 26+11=37; 37+13=50; 50+15=65;

3. 105,85,60,30,0,-45,-90

Answer : 0

Explanation : 105-20=85; 85-25=60; 60-30=30; 30-35=-5; -5-40=-45; -45-45=-90;

Exercise 3

Solve the following.

1. What is the number of zeros at the end of the product of the numbers from 1 to 100?

Answer : 127

2. A fast typist can type some matter in 2 hours and a slow typist can type the same in 3 hours. If both type combinely, in how much time will they finish?

Answer : 1 hr 12 min

Explanation : The fast typist's work done in 1 hr = 1/2

The slow typist's work done in 1 hr = 1/3

If they work combinely, work done in 1 hr = 1/2+1/3 = 5/6

So, the work will be completed in 6/5 hours. i.e., 1+1/5 hours = 1hr 12 min

3. Gavaskar's average in his first 50 innings was 50. After the 51st innings, his average was 51. How many runs did he score in his 51st innings. (supposing that he lost his wicket in his 51st innings)

Answer : 101

Explanation : Total score after 50 innings = 50*50 = 2500

Total score after 51 innings = 51*51 = 2601

So, runs made in the 51st innings = 2601-2500 = 101

If he had not lost his wicket in his 51st innings, he would have scored an unbeaten 50 in his 51st innings.

4. Out of 80 coins, one is counterfeit. What is the minimum number of weighings needed to find out the counterfeit coin?

Answer : 4

5. What can you conclude from the statement : All green are blue, all blue are red. ?

(i) some blue are green

(ii) some red are green

(iii) some green are not red

(iv) all red are blue

(a) i or ii but not both

(b) i & ii only

(d) iii & iv

Answer : (b)

6. A rectangular plate with length 8 inches, breadth 11 inches and thickness 2 inches is available. What is the length of the circular rod with diameter 8 inches and equal to the volume of the rectangular plate?

Answer : 3.5 inches

Explanation : Volume of the circular rod (cylinder) = Volume of the rectangular plate

(22/7)*4*4*h = 8*11*2

h = 7/2 = 3.5

7. What is the sum of all numbers between 100 and 1000 which are divisible by 14 ?

Answer : 35392

Explanation : The number closest to 100 which is greater than 100 and divisible by 14 is 112, which is the first term of the series which has to be summed.

The number closest to 1000 which is less than 1000 and divisible by 14 is 994, which is the last term of the series.

112 + 126 + .... + 994 = 14(8+9+ ... + 71) = 35392

8. If s(a) denotes square root of a, find the value of s(12+s(12+s(12+ ...... upto infinity.

Answer : 4

Explanation : Let x = s(12+s(12+s(12+.....

We can write x = s(12+x). i.e., x^2 = 12 + x. Solving this quadratic equation, we get x = -3 or x=4. Sum cannot be -ve and hence sum = 4.

9. A cylindrical container has a radius of eight inches with a height of three inches. Compute how many inches should be added to either the radius or height to give the same increase in volume?

Answer : 16/3 inches

Explanation : Let x be the amount of increase. The volume will increase by the same amount if the radius increased or the height is increased.

So, the effect on increasing height is equal to the effect on increasing the radius.

i.e., (22/7)*8*8*(3+x) = (22/7)*(8+x)*(8+x)*3

Solving the quadratic equation we get the x = 0 or 16/3. The possible increase would be by 16/3 inches.

10. With just six weights and a balance scale, you can weigh any unit number of kgs from 1 to 364. What could be the six weights?

Answer : 1, 3, 9, 27, 81, 243 (All powers of 3)

11. Diophantus passed one sixth of his life in childhood, one twelfth in youth, and one seventh more as a bachelor; five years after his marriage a son was born who died four years before his father at half his final age. How old is Diophantus?

Answer : 84 years

Explanation : x/6 + x/12 + x/7 + 5 + x/2 + 4 = x

12 . If time at this moment is 9 P.M., what will be the time 23999999992 hours later?

Answer : 1 P.M.

Explanation : 24 billion hours later, it would be 9 P.M. and 8 hours before that it would be 1 P.M.

13. How big will an angle of one and a half degree look through a glass that magnifies things three times?

Answer : 1 1/2 degrees

Explanation : The magnifying glass cannot increase the magnitude of an angle.

14. Divide 45 into four parts such that when 2 is added to the first part, 2 is subtracted from the second part, 2 is multiplied by the third part and the fourth part is divided by two, all result in the same number.

Answer: 8, 12, 5, 20

Explanation: a + b + c + d =45; a+2 = b-2 = 2c = d/2; a=b-4; c = (b-2)/2; d = 2(b-2); b-4 + b + (b-2)/2 + 2(b-2) = 45;

15. I drove 60 km at 30 kmph and then an additional 60 km at 50 kmph. Compute my average speed over my 120 km.

Answer : 37 1/2

Explanation : Time reqd for the first 60 km = 120 min.; Time reqd for the second 60 km = 72 min.; Total time reqd = 192 min

Avg speed = (60*120)/192 = 37 1/2

Questions 16 and 17 are based on the following :

Five executives of European Corporation hold a Conference in Rome

Mr. A converses in Spanish & Italian

Mr. B, a spaniard, knows English also

Mr. C knows English and belongs to Italy

Mr. D converses in French and Spanish

Mr. E , a native of Italy knows French

16. Which of the following can act as interpreter if Mr. C & Mr. D wish to converse

a) only Mr. A b) Only Mr. B c) Mr. A & Mr. B d) Any of the other three

Answer : d) Any of the other three.

Explanation : From the data given, we can infer the following.

A knows Spanish, Italian

B knows Spanish, English

C knows Italian, English

D knows Spanish, French

E knows Italian, French

To act as an interpreter between C and D, a person has to know one of the combinations Italian&Spanish, Italian&French, English&Spanish, English&French

A, B, and E know atleast one of the combinations.

17. If a 6th executive is brought in, to be understood by maximum number of original five he should be fluent in

a) English & French b) Italian & Spanish c) English & French d) French & Italian

Answer : b) Italian & Spanish

Explanation : No of executives who know

i) English is 2

ii) Spanish is 3

iii) Italian is 3

iv) French is 2

Italian & Spanish are spoken by the maximum no of executives. So, if the 6th executive is fluent in Italian & Spanish, he can communicate with all the original five because everybody knows either Spanish or Italian.

What is the sum of the first 25 natural odd numbers?

Answer : 625

Explanation : The sum of the first n natural odd nos is square(n).

1+3 = 4 = square(2) 1+3+5 = 9 = square(3)

The sum of any seven consecutive numbers is divisible by

a) 2 b) 7 c) 3 d) 11

Exercise 3

Try the following.

There are seventy clerks working in a company, of which 30 are females. Also, 30 clerks are married; 24 clerks are above 25 years of age; 19 married clerks are above 25 years, of which 7 are males; 12 males are above 25 years of age; and 15 males are married. How many bachelor girls are there and how many of these are above 25?

A man sailed off from the North Pole. After covering 2,000 miles in one direction he turned West, sailed 2,000 miles, turned North and sailed ahead another 2,000 miles till he met his friend. How far was he from the North Pole and in what direction?

Here is a series of comments on the ages of three persons J, R, S by themselves.

S : The difference between R's age and mine is three years.

J : R is the youngest.

R : Either I am 24 years old or J 25 or S 26.

J : All are above 24 years of age.

S : I am the eldest if and only if R is not the youngest.

R : S is elder to me.

J : I am the eldest.

R : S is not 27 years old.

S : The sum of my age and J's is two more than twice R's age.

One of the three had been telling a lie throughout whereas others had spoken the truth. Determine the ages of S,J,R.

In a group of five people, what is the probability of finding two persons with the same month of birth?

A father and his son go out for a 'walk-and-run' every morning around a track formed by an equilateral triangle. The father's walking speed is 2 mph and his running speed is 5 mph. The son's walking and running speeds are twice that of his father. Both start together from one apex of the triangle, the son going clockwise and the father anti-clockwise. Initially the father runs and the son walks for a certain period of time. Thereafter, as soon as the father starts walking, the son starts running. Both complete the course in 45 minutes. For how long does the father run? Where do the two cross each other?

The Director of Medical Services was on his annual visit to the ENT Hospital. While going through the out patients' records he came across the following data for a particular day : " Ear consultations 45; Nose 50; Throat 70; Ear and Nose 30; Nose and Throat 20; Ear and Throat 30; Ear, Nose and Throat 10; Total patients 100." Then he came to the conclusion that the records were bogus. Was he right?

Amongst Ram, Sham and Gobind are a doctor, a lawyer and a police officer. They are married to Radha, Gita and Sita (not in order). Each of the wives have a profession. Gobind's wife is an artist. Ram is not married to Gita. The lawyer's wife is a teacher. Radha is married to the police officer. Sita is an expert cook. Who's who?

What should come next?

1, 2, 4, 10, 16, 40, 64,

Questions 9-12 are based on the following :

Three adults – Roberto, Sarah and Vicky – will be traveling in a van with five children – Freddy, Hillary, Jonathan, Lupe, and Marta. The van has a driver’s seat and one passenger seat in the front, and two benches behind the front seats, one beach behind the other. Each bench has room for exactly three people. Everyone must sit in a seat or on a bench, and seating is subject to the following restrictions: An adult must sit on each bench.

Either Roberto or Sarah must sit in the driver’s seat.

Jonathan must sit immediately beside Marta.

Of the following, who can sit in the front passenger seat ?

(a) Jonathan (b) Lupe (c) Roberto (d) Sarah (e) Vicky

10. Which of the following groups of three can sit together on a bench?

(a) Freddy, Jonathan and Marta (b) Freddy, Jonathan and Vicky

(e) Lupe, Marta and Roberto

If Freddy sits immediately beside Vicky, which of the following cannot be true ?

Jonathan sits immediately beside Sarah
Lupe sits immediately beside Vicky
Hillary sits in the front passenger seat
Freddy sits on the same bench as Hillary
Hillary sits on the same bench as Roberto

If Sarah sits on a bench that is behind where Jonathan is sitting, which of the following must be true ?

Hillary sits in a seat or on a bench that is in front of where Marta is sitting
Lupe sits in a seat or on a bench that is in front of where Freddy is sitting
Freddy sits on the same bench as Hillary
Lupe sits on the same bench as Sarah
Marta sits on the same bench as Vicky

Make six squares of the same size using twelve match-sticks. (Hint : You will need an adhesive to arrange the required figure)

A farmer has two rectangular fields. The larger field has twice the length and 4 times the width of the smaller field. If the smaller field has area K, then the are of the larger field is greater than the area of the smaller field by what amount?

(a) 6K (b) 8K (c) 12K (d) 7K

Nine equal circles are enclosed in a square whose area is 36sq units. Find the area of each circle.

There are 9 cards. Arrange them in a 3*3 matrix. Cards are of 4 colors. They are red, yellow, blue, green. Conditions for arrangement: one red card must be in first row or second row. 2 green cards should be in 3^rd column. Yellow cards must be in the 3 corners only. Two blue cards must be in the 2nd row. At least one green card in each row.

Is z less than w? z and w are real numbers.

(I) z² = 25

(II) w = 9

To answer the question,

a) Either I or II is sufficient

b) Both I and II are sufficient but neither of them is alone sufficient

c) I & II are sufficient

d) Both are not sufficient

A speaks truth 70% of the time; B speaks truth 80% of the time. What is the probability that both are contradicting each other?

In a family 7 children don't eat spinach, 6 don't eat carrot, 5 don't eat beans, 4 don't eat spinach & carrots, 3 don't eat carrot & beans, 2 don't eat beans & spinach. One doesn't eat all 3. Find the no. of children.

Anna, Bena, Catherina and Diana are at their monthly business meeting. Their occupations are author, biologist, chemist and doctor, but not necessarily in that order. Diana just told the neighbour, who is a biologist that Catherina was on her way with doughnuts. Anna is sitting across from the doctor and next to the chemist. The doctor was thinking that Bena was a good name for parent's to choose, but didn't say anything. What is each person's occupation?

C Questions Aptitude

Note : All the programs are tested under Turbo C/C++ compilers.
It is assumed that,
Programs run under DOS environment,
The underlying machine is an x86 system,
Program is compiled using Turbo C/C++ compiler.
The program output may depend on the information based on this assumptions (for example sizeof(int) == 2 may be assumed).

Predict the output or error(s) for the following:

void main()
{
int const * p=5;
printf("%d",++(*p));
}
Answer:
Compiler error: Cannot modify a constant value.
Explanation:
p is a pointer to a "constant integer". But we tried to change the value of the "constant integer".

main()
{
char s[ ]="man";
int i;
for(i=0;s[ i ];i++)
printf("\n%c%c%c%c",s[ i ],*(s+i),*(i+s),i[s]);
}
Answer:
mmmm
aaaa
nnnn
Explanation:
s[i], *(i+s), *(s+i), i[s] are all different ways of expressing the same idea. Generally array name is the base address for that array. Here s is the base address. i is the index number/displacement from the base address. So, indirecting it with * is same as s[i]. i[s] may be surprising. But in the case of C it is same as s[i].

main()
{
float me = 1.1;
double you = 1.1;
if(me==you)
printf("I love U");
else
printf("I hate U");
}
Answer:
I hate U
Explanation:
For floating point numbers (float, double, long double) the values cannot be predicted exactly. Depending on the number of bytes, the precession with of the value represented varies. Float takes 4 bytes and long double takes 10 bytes. So float stores 0.9 with less precision than long double.
Rule of Thumb:
Never compare or at-least be cautious when using floating point numbers with relational operators (== , >, <, <=, >=,!= ) .

main()
{
static int var = 5;
printf("%d ",var--);
if(var)
main();
}
Answer:
5 4 3 2 1
Explanation:
When static storage class is given, it is initialized once. The change in the value of a static variable is retained even between the function calls. Main is also treated like any other ordinary function, which can be called recursively.

main()
{
int c[ ]={2.8,3.4,4,6.7,5};
int j,*p=c,*q=c;
for(j=0;j<5;j++) {
printf(" %d ",*c);
++q; }
for(j=0;j<5;j++){
printf(" %d ",*p);
++p; }
}

Answer:
2 2 2 2 2 2 3 4 6 5
Explanation:
Initially pointer c is assigned to both p and q. In the first loop, since only q is incremented and not c , the value 2 will be printed 5 times. In second loop p itself is incremented. So the values 2 3 4 6 5 will be printed.

main()
{
extern int i;
i=20;
printf("%d",i);
}

Answer:
Linker Error : Undefined symbol '_i'
Explanation:
extern storage class in the following declaration,
extern int i;
specifies to the compiler that the memory for i is allocated in some other program and that address will be given to the current program at the time of linking. But linker finds that no other variable of name i is available in any other program with memory space allocated for it. Hence a linker error has occurred .

main()
{
int i=-1,j=-1,k=0,l=2,m;
m=i++&&j++&&k++||l++;
printf("%d %d %d %d %d",i,j,k,l,m);
}
Answer:
0 0 1 3 1
Explanation :
Logical operations always give a result of 1 or 0 . And also the logical AND (&&) operator has higher priority over the logical OR (||) operator. So the expression ‘i++ && j++ && k++’ is executed first. The result of this expression is 0 (-1 && -1 && 0 = 0). Now the expression is 0 || 2 which evaluates to 1 (because OR operator always gives 1 except for ‘0 || 0’ combination- for which it gives 0). So the value of m is 1. The values of other variables are also incremented by 1.

main()
{
char *p;
printf("%d %d ",sizeof(*p),sizeof(p));
}

Answer:
1 2
Explanation:
The sizeof() operator gives the number of bytes taken by its operand. P is a character pointer, which needs one byte for storing its value (a character). Hence sizeof(*p) gives a value of 1. Since it needs two bytes to store the address of the character pointer sizeof(p) gives 2.

main()
{
int i=3;
switch(i)
{
default:printf("zero");
case 1: printf("one");
break;
case 2:printf("two");
break;
case 3: printf("three");
break;
}
}
Answer :
three
Explanation :
The default case can be placed anywhere inside the loop. It is executed only when all other cases doesn't match.

main()
{
printf("%x",-1<<4);
}
Answer:
fff0
Explanation :
-1 is internally represented as all 1's. When left shifted four times the least significant 4 bits are filled with 0's.The %x format specifier specifies that the integer value be printed as a hexadecimal value.

main()
{
char string[]="Hello World";
display(string);
}
void display(char *string)
{
printf("%s",string);
}
Answer:
Compiler Error : Type mismatch in redeclaration of function display
Explanation :
In third line, when the function display is encountered, the compiler doesn't know anything about the function display. It assumes the arguments and return types to be integers, (which is the default type). When it sees the actual function display, the arguments and type contradicts with what it has assumed previously. Hence a compile time error occurs.

main()
{
int c=- -2;
printf("c=%d",c);
}
Answer:
c=2;
Explanation:
Here unary minus (or negation) operator is used twice. Same maths rules applies, ie. minus * minus= plus.
Note:
However you cannot give like --2. Because -- operator can only be applied to variables as a decrement operator (eg., i--). 2 is a constant and not a variable.

#define int char
main()
{
int i=65;
printf("sizeof(i)=%d",sizeof(i));
}
Answer:
sizeof(i)=1
Explanation:
Since the #define replaces the string int by the macro char

main()
{
int i=10;
i=!i>14;
Printf ("i=%d",i);
}
Answer:
i=0

Explanation:
In the expression !i>14 , NOT (!) operator has more precedence than ‘ >’ symbol. ! is a unary logical operator. !i (!10) is 0 (not of true is false). 0>14 is false (zero).

#include<stdio.h>
main()
{
char s[]={'a','b','c','\n','c','\0'};
char *p,*str,*str1;
p=&s[3];
str=p;
str1=s;
printf("%d",++*p + ++*str1-32);
}
Answer:
77
Explanation:
p is pointing to character '\n'. str1 is pointing to character 'a' ++*p. "p is pointing to '\n' and that is incremented by one." the ASCII value of '\n' is 10, which is then incremented to 11. The value of ++*p is 11. ++*str1, str1 is pointing to 'a' that is incremented by 1 and it becomes 'b'. ASCII value of 'b' is 98.
Now performing (11 + 98 – 32), we get 77("M");
So we get the output 77 :: "M" (Ascii is 77).

#include<stdio.h>
main()
{
int a[2][2][2] = { {10,2,3,4}, {5,6,7,8} };
int *p,*q;
p=&a[2][2][2];
*q=***a;
printf("%d----%d",*p,*q);
}
Answer:
SomeGarbageValue---1
Explanation:
p=&a[2][2][2] you declare only two 2D arrays, but you are trying to access the third 2D(which you are not declared) it will print garbage values. *q=***a starting address of a is assigned integer pointer. Now q is pointing to starting address of a. If you print *q, it will print first element of 3D array.

#include<stdio.h>
main()
{
struct xx
{
int x=3;
char name[]="hello";
};
struct xx *s;
printf("%d",s->x);
printf("%s",s->name);
}
Answer:
Compiler Error
Explanation:
You should not initialize variables in declaration

#include<stdio.h>
main()
{
struct xx
{
int x;
struct yy
{
char s;
struct xx *p;
};
struct yy *q;
};
}
Answer:
Compiler Error
Explanation:
The structure yy is nested within structure xx. Hence, the elements are of yy are to be accessed through the instance of structure xx, which needs an instance of yy to be known. If the instance is created after defining the structure the compiler will not know about the instance relative to xx. Hence for nested structure yy you have to declare member.

main()
{
printf("\nab");
printf("\bsi");
printf("\rha");
}
Answer:
hai
Explanation:
\n - newline
\b - backspace
\r - linefeed

main()
{
int i=5;
printf("%d%d%d%d%d%d",i++,i--,++i,--i,i);
}
Answer:
45545
Explanation:
The arguments in a function call are pushed into the stack from left to right. The evaluation is by popping out from the stack. and the evaluation is from right to left, hence the result.

#define square(x) x*x
main()
{
int i;
i = 64/square(4);
printf("%d",i);
}
Answer:
64
Explanation:
the macro call square(4) will substituted by 4*4 so the expression becomes i = 64/4*4 . Since / and * has equal priority the expression will be evaluated as (64/4)*4 i.e. 16*4 = 64

main()
{
char *p="hai friends",*p1;
p1=p;
while(*p!='\0') ++*p++;
printf("%s %s",p,p1);
}
Answer:
ibj!gsjfoet
Explanation:
++*p++ will be parse in the given order
*p that is value at the location currently pointed by p will be taken
++*p the retrieved value will be incremented
when ; is encountered the location will be incremented that is p++ will be executed
Hence, in the while loop initial value pointed by p is ‘h’, which is changed to ‘i’ by executing ++*p and pointer moves to point, ‘a’ which is similarly changed to ‘b’ and so on. Similarly blank space is converted to ‘!’. Thus, we obtain value in p becomes “ibj!gsjfoet” and since p reaches ‘\0’ and p1 points to p thus p1doesnot print anything.

#include <stdio.h>
#define a 10
main()
{
#define a 50
printf("%d",a);
}
Answer:
50
Explanation:
The preprocessor directives can be redefined anywhere in the program. So the most recently assigned value will be taken.

#define clrscr() 100
main()
{
clrscr();
printf("%d\n",clrscr());
}
Answer:
100
Explanation:
Preprocessor executes as a seperate pass before the execution of the compiler. So textual replacement of clrscr() to 100 occurs.The input program to compiler looks like this :
main()
{
100;
printf("%d\n",100);
}
Note:
100; is an executable statement but with no action. So it doesn't give any problem

main()
{
printf("%p",main);
}
Answer:
Some address will be printed.
Explanation:
Function names are just addresses (just like array names are addresses).
main() is also a function. So the address of function main will be printed. %p in printf specifies that the argument is an address. They are printed as hexadecimal numbers.

27) main()
{
clrscr();
}
clrscr();

Answer:
No output/error
Explanation:
The first clrscr() occurs inside a function. So it becomes a function call. In the second clrscr(); is a function declaration (because it is not inside any function).

28) enum colors {BLACK,BLUE,GREEN}
main()
{

printf("%d..%d..%d",BLACK,BLUE,GREEN);

return(1);
}
Answer:
0..1..2
Explanation:
enum assigns numbers starting from 0, if not explicitly defined.

29) void main()
{
char far *farther,*farthest;

printf("%d..%d",sizeof(farther),sizeof(farthest));

}
Answer:
4..2
Explanation:
the second pointer is of char type and not a far pointer

30) main()
{
int i=400,j=300;
printf("%d..%d");
}
Answer:
400..300
Explanation:
printf takes the values of the first two assignments of the program. Any number of printf's may be given. All of them take only the first two values. If more number of assignments given in the program,then printf will take garbage values.

31) main()
{
char *p;
p="Hello";
printf("%c\n",*&*p);
}
Answer:
H
Explanation:
* is a dereference operator & is a reference operator. They can be applied any number of times provided it is meaningful. Here p points to the first character in the string "Hello". *p dereferences it and so its value is H. Again & references it to an address and * dereferences it to the value H.

32) main()
{
int i=1;
while (i<=5)
{
printf("%d",i);
if (i>2)
goto here;
i++;
}
}
fun()
{
here:
printf("PP");
}
Answer:
Compiler error: Undefined label 'here' in function main
Explanation:
Labels have functions scope, in other words The scope of the labels is limited to functions . The label 'here' is available in function fun() Hence it is not visible in function main.

33) main()
{
static char names[5][20]={"pascal","ada","cobol","fortran","perl"};
int i;
char *t;
t=names[3];
names[3]=names[4];
names[4]=t;
for (i=0;i<=4;i++)
printf("%s",names[i]);
}
Answer:
Compiler error: Lvalue required in function main
Explanation:
Array names are pointer constants. So it cannot be modified.

34) void main()
{
int i=5;
printf("%d",i++ + ++i);
}
Answer:
Output Cannot be predicted exactly.
Explanation:
Side effects are involved in the evaluation of i

35) void main()
{
int i=5;
printf("%d",i+++++i);
}
Answer:
Compiler Error
Explanation:
The expression i+++++i is parsed as i ++ ++ + i which is an illegal combination of operators.

36) #include<stdio.h>
main()
{
int i=1,j=2;
switch(i)
{
case 1: printf("GOOD");
break;
case j: printf("BAD");
break;
}
}
Answer:
Compiler Error: Constant expression required in function main.
Explanation:
The case statement can have only constant expressions (this implies that we cannot use variable names directly so an error).
Note:
Enumerated types can be used in case statements.

37) main()
{
int i;
printf("%d",scanf("%d",&i)); // value 10 is given as input here
}
Answer:
1
Explanation:
Scanf returns number of items successfully read and not 1/0. Here 10 is given as input which should have been scanned successfully. So number of items read is 1.

38) #define f(g,g2) g##g2
main()
{
int var12=100;
printf("%d",f(var,12));
}
Answer:
100

39) main()
{
int i=0;

for(;i++;printf("%d",i)) ;
printf("%d",i);
}
Answer:
1
Explanation:
before entering into the for loop the checking condition is "evaluated". Here it evaluates to 0 (false) and comes out of the loop, and i is incremented (note the semicolon after the for loop).

40) #include<stdio.h>
main()
{
char s[]={'a','b','c','\n','c','\0'};
char *p,*str,*str1;
p=&s[3];
str=p;
str1=s;
printf("%d",++*p + ++*str1-32);
}
Answer:
M
Explanation:
p is pointing to character '\n'.str1 is pointing to character 'a' ++*p meAnswer:"p is pointing to '\n' and that is incremented by one." the ASCII value of '\n' is 10. then it is incremented to 11. the value of ++*p is 11. ++*str1 meAnswer:"str1 is pointing to 'a' that is incremented by 1 and it becomes 'b'. ASCII value of 'b' is 98. both 11 and 98 is added and result is subtracted from 32.
i.e. (11+98-32)=77("M");

41) #include<stdio.h>
main()
{
struct xx
{
int x=3;
char name[]="hello";
};
struct xx *s=malloc(sizeof(struct xx));
printf("%d",s->x);
printf("%s",s->name);
}
Answer:
Compiler Error
Explanation:
Initialization should not be done for structure members inside the structure declaration

42) #include<stdio.h>
main()
{
struct xx
{
int x;
struct yy
{
char s;
struct xx *p;
};
struct yy *q;
};
}
Answer:
Compiler Error
Explanation:
in the end of nested structure yy a member have to be declared.

43) main()
{
extern int i;
i=20;
printf("%d",sizeof(i));
}
Answer:
Linker error: undefined symbol '_i'.
Explanation:
extern declaration specifies that the variable i is defined somewhere else. The compiler passes the external variable to be resolved by the linker. So compiler doesn't find an error. During linking the linker searches for the definition of i. Since it is not found the linker flags an error.

44) main()
{
printf("%d", out);
}
int out=100;
Answer:
Compiler error: undefined symbol out in function main.
Explanation:
The rule is that a variable is available for use from the point of declaration. Even though a is a global variable, it is not available for main. Hence an error.

45) main()
{
extern out;
printf("%d", out);
}
int out=100;
Answer:
100
Explanation:
This is the correct way of writing the previous program.

46) main()
{
show();
}
void show()
{
printf("I'm the greatest");
}
Answer:
Compier error: Type mismatch in redeclaration of show.
Explanation:
When the compiler sees the function show it doesn't know anything about it. So the default return type (ie, int) is assumed. But when compiler sees the actual definition of show mismatch occurs since it is declared as void. Hence the error.
The solutions are as follows:
1. declare void show() in main() .
2. define show() before main().
3. declare extern void show() before the use of show().

47) main( )
{
int a[2][3][2] = {{{2,4},{7,8},{3,4}},{{2,2},{2,3},{3,4}}};
printf(“%u %u %u %d \n”,a,*a,**a,***a);
printf(“%u %u %u %d \n”,a+1,*a+1,**a+1,***a+1);
}
Answer:
100, 100, 100, 2
114, 104, 102, 3
Explanation:
The given array is a 3-D one. It can also be viewed as a 1-D array.

2 4 7 8 3 4 2 2 2 3 3 4
100 102 104 106 108 110 112 114 116 118 120 122

thus, for the first printf statement a, *a, **a give address of first element . since the indirection ***a gives the value. Hence, the first line of the output.
for the second printf a+1 increases in the third dimension thus points to value at 114, *a+1 increments in second dimension thus points to 104, **a +1 increments the first dimension thus points to 102 and ***a+1 first gets the value at first location and then increments it by 1. Hence, the output.

48) main( )
{
int a[ ] = {10,20,30,40,50},j,*p;
for(j=0; j<5; j++)
{
printf(“%d” ,*a);
a++;
}
p = a;
for(j=0; j<5; j++)
{
printf(“%d ” ,*p);
p++;
}
}
Answer:
Compiler error: lvalue required.

Explanation:
Error is in line with statement a++. The operand must be an lvalue and may be of any of scalar type for the any operator, array name only when subscripted is an lvalue. Simply array name is a non-modifiable lvalue.

49) main( )
{
static int a[ ] = {0,1,2,3,4};
int *p[ ] = {a,a+1,a+2,a+3,a+4};
int **ptr = p;
ptr++;
printf(“\n %d %d %d”, ptr-p, *ptr-a, **ptr);
*ptr++;
printf(“\n %d %d %d”, ptr-p, *ptr-a, **ptr);
*++ptr;
printf(“\n %d %d %d”, ptr-p, *ptr-a, **ptr);
++*ptr;
printf(“\n %d %d %d”, ptr-p, *ptr-a, **ptr);
}
Answer:
111
222
333
344
Explanation:
Let us consider the array and the two pointers with some address
a

0 1 2 3 4
100 102 104 106 108
p

100 102 104 106 108
1000 1002 1004 1006 1008
ptr

1000
2000
After execution of the instruction ptr++ value in ptr becomes 1002, if scaling factor for integer is 2 bytes. Now ptr – p is value in ptr – starting location of array p, (1002 – 1000) / (scaling factor) = 1, *ptr – a = value at address pointed by ptr – starting value of array a, 1002 has a value 102 so the value is (102 – 100)/(scaling factor) = 1, **ptr is the value stored in the location pointed by the pointer of ptr = value pointed by value pointed by 1002 = value pointed by 102 = 1. Hence the output of the firs printf is 1, 1, 1.
After execution of *ptr++ increments value of the value in ptr by scaling factor, so it becomes1004. Hence, the outputs for the second printf are ptr – p = 2, *ptr – a = 2, **ptr = 2.
After execution of *++ptr increments value of the value in ptr by scaling factor, so it becomes1004. Hence, the outputs for the third printf are ptr – p = 3, *ptr – a = 3, **ptr = 3.
After execution of ++*ptr value in ptr remains the same, the value pointed by the value is incremented by the scaling factor. So the value in array p at location 1006 changes from 106 10 108,. Hence, the outputs for the fourth printf are ptr – p = 1006 – 1000 = 3, *ptr – a = 108 – 100 = 4, **ptr = 4.

50) main( )
{
char *q;
int j;
for (j=0; j<3; j++) scanf(“%s” ,(q+j));
for (j=0; j<3; j++) printf(“%c” ,*(q+j));
for (j=0; j<3; j++) printf(“%s” ,(q+j));
}
Explanation:
Here we have only one pointer to type char and since we take input in the same pointer thus we keep writing over in the same location, each time shifting the pointer value by 1. Suppose the inputs are MOUSE, TRACK and VIRTUAL. Then for the first input suppose the pointer starts at location 100 then the input one is stored as

M O U S E \0
When the second input is given the pointer is incremented as j value becomes 1, so the input is filled in memory starting from 101.

M T R A C K \0
The third input starts filling from the location 102

M T V I R T U A L \0
This is the final value stored .
The first printf prints the values at the position q, q+1 and q+2 = M T V
The second printf prints three strings starting from locations q, q+1, q+2
i.e MTVIRTUAL, TVIRTUAL and VIRTUAL.

51) main( )
{
void *vp;
char ch = ‘g’, *cp = “goofy”;
int j = 20;
vp = &ch;
printf(“%c”, *(char *)vp);
vp = &j;
printf(“%d”,*(int *)vp);
vp = cp;
printf(“%s”,(char *)vp + 3);
}
Answer:
g20fy
Explanation:
Since a void pointer is used it can be type casted to any other type pointer. vp = &ch stores address of char ch and the next statement prints the value stored in vp after type casting it to the proper data type pointer. the output is ‘g’. Similarly the output from second printf is ‘20’. The third printf statement type casts it to print the string from the 4th value hence the output is ‘fy’.

52) main ( )
{
static char *s[ ] = {“black”, “white”, “yellow”, “violet”};
char **ptr[ ] = {s+3, s+2, s+1, s}, ***p;
p = ptr;
**++p;
printf(“%s”,*--*++p + 3);
}
Answer:
ck
Explanation:
In this problem we have an array of char pointers pointing to start of 4 strings. Then we have ptr which is a pointer to a pointer of type char and a variable p which is a pointer to a pointer to a pointer of type char. p hold the initial value of ptr, i.e. p = s+3. The next statement increment value in p by 1 , thus now value of p = s+2. In the printf statement the expression is evaluated *++p causes gets value s+1 then the pre decrement is executed and we get s+1 – 1 = s . the indirection operator now gets the value from the array of s and adds 3 to the starting address. The string is printed starting from this position. Thus, the output is ‘ck’.

53) main()
{
int i, n;
char *x = “girl”;
n = strlen(x);
*x = x[n];
for(i=0; i<n; ++i)
{
printf(“%s\n”,x);
x++;
}
}
Answer:
(blank space)
irl
rl
l

Explanation:
Here a string (a pointer to char) is initialized with a value “girl”. The strlen function returns the length of the string, thus n has a value 4. The next statement assigns value at the nth location (‘\0’) to the first location. Now the string becomes “\0irl” . Now the printf statement prints the string after each iteration it increments it starting position. Loop starts from 0 to 4. The first time x[0] = ‘\0’ hence it prints nothing and pointer value is incremented. The second time it prints from x[1] i.e “irl” and the third time it prints “rl” and the last time it prints “l” and the loop terminates.
54) int i,j;
for(i=0;i<=10;i++)
{
j+=5;
assert(i<5);
}
Answer:
Runtime error: Abnormal program termination.
assert failed (i<5), <file name>,<line number>
Explanation:
asserts are used during debugging to make sure that certain conditions are satisfied. If assertion fails, the program will terminate reporting the same. After debugging use,
#undef NDEBUG
and this will disable all the assertions from the source code. Assertion
is a good debugging tool to make use of.

55) main()
{
int i=-1;
+i;
printf("i = %d, +i = %d \n",i,+i);
}
Answer:
i = -1, +i = -1
Explanation:
Unary + is the only dummy operator in C. Where-ever it comes you can just ignore it just because it has no effect in the expressions (hence the name dummy operator).

56) What are the files which are automatically opened when a C file is executed?
Answer:
stdin, stdout, stderr (standard input,standard output,standard error).

57) what will be the position of the file marker?
a: fseek(ptr,0,SEEK_SET);
b: fseek(ptr,0,SEEK_CUR);

Answer :
a: The SEEK_SET sets the file position marker to the starting of the file.
b: The SEEK_CUR sets the file position marker to the current position
of the file.

58) main()
{
char name[10],s[12];
scanf(" \"%[^\"]\"",s);
}
How scanf will execute?
Answer:
First it checks for the leading white space and discards it.Then it matches with a quotation mark and then it reads all character upto another quotation mark.

59) What is the problem with the following code segment?
while ((fgets(receiving array,50,file_ptr)) != EOF)
;
Answer & Explanation:
fgets returns a pointer. So the correct end of file check is checking for != NULL.

60) main()
{
main();
}
Answer:
Runtime error : Stack overflow.
Explanation:
main function calls itself again and again. Each time the function is called its return address is stored in the call stack. Since there is no condition to terminate the function call, the call stack overflows at runtime. So it terminates the program and results in an error.

61) main()
{
char *cptr,c;
void *vptr,v;
c=10; v=0;
cptr=&c; vptr=&v;
printf("%c%v",c,v);
}
Answer:
Compiler error (at line number 4): size of v is Unknown.
Explanation:
You can create a variable of type void * but not of type void, since void is an empty type. In the second line you are creating variable vptr of type void * and v of type void hence an error.

62) main()
{
char *str1="abcd";
char str2[]="abcd";
printf("%d %d %d",sizeof(str1),sizeof(str2),sizeof("abcd"));
}
Answer:
2 5 5
Explanation:
In first sizeof, str1 is a character pointer so it gives you the size of the pointer variable. In second sizeof the name str2 indicates the name of the array whose size is 5 (including the '\0' termination character). The third sizeof is similar to the second one.

63) main()
{
char not;
not=!2;
printf("%d",not);
}
Answer:
0
Explanation:
! is a logical operator. In C the value 0 is considered to be the boolean value FALSE, and any non-zero value is considered to be the boolean value TRUE. Here 2 is a non-zero value so TRUE. !TRUE is FALSE (0) so it prints 0.

64) #define FALSE -1
#define TRUE 1
#define NULL 0
main() {
if(NULL)
puts("NULL");
else if(FALSE)
puts("TRUE");
else
puts("FALSE");
}
Answer:
TRUE
Explanation:
The input program to the compiler after processing by the preprocessor is,
main(){
if(0)
puts("NULL");
else if(-1)
puts("TRUE");
else
puts("FALSE");
}
Preprocessor doesn't replace the values given inside the double quotes. The check by if condition is boolean value false so it goes to else. In second if -1 is boolean value true hence "TRUE" is printed.

65) main()
{
int k=1;
printf("%d==1 is ""%s",k,k==1?"TRUE":"FALSE");
}
Answer:
1==1 is TRUE
Explanation:
When two strings are placed together (or separated by white-space) they are concatenated (this is called as "stringization" operation). So the string is as if it is given as "%d==1 is %s". The conditional operator( ?: ) evaluates to "TRUE".

66) main()
{
int y;
scanf("%d",&y); // input given is 2000
if( (y%4==0 && y%100 != 0) || y%100 == 0 )
printf("%d is a leap year");
else
printf("%d is not a leap year");
}
Answer:
2000 is a leap year
Explanation:
An ordinary program to check if leap year or not.

67) #define max 5
#define int arr1[max]
main()
{
typedef char arr2[max];
arr1 list={0,1,2,3,4};
arr2 name="name";
printf("%d %s",list[0],name);
}
Answer:
Compiler error (in the line arr1 list = {0,1,2,3,4})
Explanation:
arr2 is declared of type array of size 5 of characters. So it can be used to declare the variable name of the type arr2. But it is not the case of arr1. Hence an error.
Rule of Thumb:
#defines are used for textual replacement whereas typedefs are used for declaring new types.

68) int i=10;
main()
{
extern int i;
{
int i=20;
{
const volatile unsigned i=30;
printf("%d",i);
}
printf("%d",i);
}
printf("%d",i);
}
Answer:
30,20,10
Explanation:
'{' introduces new block and thus new scope. In the innermost block i is declared as,
const volatile unsigned
which is a valid declaration. i is assumed of type int. So printf prints 30. In the next block, i has value 20 and so printf prints 20. In the outermost block, i is declared as extern, so no storage space is allocated for it. After compilation is over the linker resolves it to global variable i (since it is the only variable visible there). So it prints i's value as 10.

69) main()
{
int *j;
{
int i=10;
j=&i;
}
printf("%d",*j);
}
Answer:
10
Explanation:
The variable i is a block level variable and the visibility is inside that block only. But the lifetime of i is lifetime of the function so it lives upto the exit of main function. Since the i is still allocated space, *j prints the value stored in i since j points i.

70) main()
{
int i=-1;
-i;
printf("i = %d, -i = %d \n",i,-i);
}
Answer:
i = -1, -i = 1
Explanation:
-i is executed and this execution doesn't affect the value of i. In printf first you just print the value of i. After that the value of the expression -i = -(-1) is printed.

71) #include<stdio.h>
main()
{
const int i=4;
float j;
j = ++i;
printf("%d %f", i,++j);
}
Answer:
Compiler error
Explanation:
i is a constant. you cannot change the value of constant

72) #include<stdio.h>
main()
{
int a[2][2][2] = { {10,2,3,4}, {5,6,7,8} };
int *p,*q;
p=&a[2][2][2];
*q=***a;
printf("%d..%d",*p,*q);
}
Answer:
garbagevalue..1
Explanation:
p=&a[2][2][2] you declare only two 2D arrays. but you are trying to access the third 2D(which you are not declared) it will print garbage values. *q=***a starting address of a is assigned integer pointer. now q is pointing to starting address of a.if you print *q meAnswer:it will print first element of 3D array.

73) #include<stdio.h>
main()
{
register i=5;
char j[]= "hello";
printf("%s %d",j,i);
}
Answer:
hello 5
Explanation:
if you declare i as register compiler will treat it as ordinary integer and it will take integer value. i value may be stored either in register or in memory.

74) main()
{
int i=5,j=6,z;
printf("%d",i+++j);
}
Answer:
11
Explanation:
the expression i+++j is treated as (i++ + j)

76) struct aaa{
struct aaa *prev;
int i;
struct aaa *next;
};
main()
{
struct aaa abc,def,ghi,jkl;
int x=100;
abc.i=0;abc.prev=&jkl;
abc.next=&def;
def.i=1;def.prev=&abc;def.next=&ghi;
ghi.i=2;ghi.prev=&def;
ghi.next=&jkl;
jkl.i=3;jkl.prev=&ghi;jkl.next=&abc;
x=abc.next->next->prev->next->i;
printf("%d",x);
}
Answer:
2
Explanation:
above all statements form a double circular linked list;
abc.next->next->prev->next->i
this one points to "ghi" node the value of at particular node is 2.

77) struct point
{
int x;
int y;
};
struct point origin,*pp;
main()
{
pp=&origin;
printf("origin is(%d%d)\n",(*pp).x,(*pp).y);
printf("origin is (%d%d)\n",pp->x,pp->y);
}

Answer:
origin is(0,0)
origin is(0,0)
Explanation:
pp is a pointer to structure. we can access the elements of the structure either with arrow mark or with indirection operator.
Note:
Since structure point is globally declared x & y are initialized as zeroes

78) main()
{
int i=_l_abc(10);
printf("%d\n",--i);
}
int _l_abc(int i)
{
return(i++);
}
Answer:
9
Explanation:
return(i++) it will first return i and then increments. i.e. 10 will be returned.

79) main()
{
char *p;
int *q;
long *r;
p=q=r=0;
p++;
q++;
r++;
printf("%p...%p...%p",p,q,r);
}
Answer:
0001...0002...0004
Explanation:
++ operator when applied to pointers increments address according to their corresponding data-types.

80) main()
{
char c=' ',x,convert(z);
getc(c);
if((c>='a') && (c<='z'))
x=convert(c);
printf("%c",x);
}
convert(z)
{
return z-32;
}
Answer:
Compiler error
Explanation:
declaration of convert and format of getc() are wrong.

81) main(int argc, char **argv)
{
printf("enter the character");
getchar();
sum(argv[1],argv[2]);
}
sum(num1,num2)
int num1,num2;
{
return num1+num2;
}
Answer:
Compiler error.
Explanation:
argv[1] & argv[2] are strings. They are passed to the function sum without converting it to integer values.

82) # include <stdio.h>
int one_d[]={1,2,3};
main()
{
int *ptr;
ptr=one_d;
ptr+=3;
printf("%d",*ptr);
}
Answer:
garbage value
Explanation:
ptr pointer is pointing to out of the array range of one_d.

83) # include<stdio.h>
aaa() {
printf("hi");
}
bbb(){
printf("hello");
}
ccc(){
printf("bye");
}
main()
{
int (*ptr[3])();
ptr[0]=aaa;
ptr[1]=bbb;
ptr[2]=ccc;
ptr[2]();
}
Answer:
bye
Explanation:
ptr is array of pointers to functions of return type int.ptr[0] is assigned to address of the function aaa. Similarly ptr[1] and ptr[2] for bbb and ccc respectively. ptr[2]() is in effect of writing ccc(), since ptr[2] points to ccc.

85) #include<stdio.h>
main()
{
FILE *ptr;
char i;
ptr=fopen("zzz.c","r");
while((i=fgetch(ptr))!=EOF)
printf("%c",i);
}
Answer:
contents of zzz.c followed by an infinite loop
Explanation:
The condition is checked against EOF, it should be checked against NULL.

86) main()
{
int i =0;j=0;
if(i && j++)
printf("%d..%d",i++,j);
printf("%d..%d,i,j);
}
Answer:
0..0
Explanation:
The value of i is 0. Since this information is enough to determine the truth value of the boolean expression. So the statement following the if statement is not executed. The values of i and j remain unchanged and get printed.

87) main()
{
int i;
i = abc();
printf("%d",i);
}
abc()
{
_AX = 1000;
}
Answer:
1000
Explanation:
Normally the return value from the function is through the information from the accumulator. Here _AH is the pseudo global variable denoting the accumulator. Hence, the value of the accumulator is set 1000 so the function returns value 1000.

88) int i;
main(){
int t;
for ( t=4;scanf("%d",&i)-t;printf("%d\n",i))
printf("%d--",t--);
}
// If the inputs are 0,1,2,3 find the o/p
Answer:
4--0
3--1
2--2
Explanation:
Let us assume some x= scanf("%d",&i)-t the values during execution
will be,
t i x
4 0 -4
3 1 -2
2 2 0

89) main(){
int a= 0;int b = 20;char x =1;char y =10;
if(a,b,x,y)
printf("hello");
}
Answer:
hello
Explanation:
The comma operator has associativity from left to right. Only the rightmost value is returned and the other values are evaluated and ignored. Thus the value of last variable y is returned to check in if. Since it is a non zero value if becomes true so, "hello" will be printed.

90) main(){
unsigned int i;
for(i=1;i>-2;i--)
printf("c aptitude");
}
Explanation:
i is an unsigned integer. It is compared with a signed value. Since the both types doesn't match, signed is promoted to unsigned value. The unsigned equivalent of -2 is a huge value so condition becomes false and control comes out of the loop.

91) In the following pgm add a stmt in the function fun such that the address of
'a' gets stored in 'j'.
main(){
int * j;
void fun(int **);
fun(&j);
}
void fun(int **k) {
int a =0;
/* add a stmt here*/
}
Answer:
*k = &a
Explanation:
The argument of the function is a pointer to a pointer.

92) What are the following notations of defining functions known as?
i. int abc(int a,float b)
{
/* some code */
}
ii. int abc(a,b)
int a; float b;
{
/* some code*/
}
Answer:
i. ANSI C notation
ii. Kernighan & Ritche notation

93) main()
{
char *p;
p="%d\n";
p++;
p++;
printf(p-2,300);
}
Answer:
300
Explanation:
The pointer points to % since it is incremented twice and again decremented by 2, it points to '%d\n' and 300 is printed.

94) main(){
char a[100];
a[0]='a';a[1]]='b';a[2]='c';a[4]='d';
abc(a);
}
abc(char a[]){
a++;
printf("%c",*a);
a++;
printf("%c",*a);
}
Explanation:
The base address is modified only in function and as a result a points to 'b' then after incrementing to 'c' so bc will be printed.

95) func(a,b)
int a,b;
{
return( a= (a==b) );
}
main()
{
int process(),func();
printf("The value of process is %d !\n ",process(func,3,6));
}
process(pf,val1,val2)
int (*pf) ();
int val1,val2;
{
return((*pf) (val1,val2));
}
Answer:
The value if process is 0 !
Explanation:
The function 'process' has 3 parameters - 1, a pointer to another function 2 and 3, integers. When this function is invoked from main, the following substitutions for formal parameters take place: func for pf, 3 for val1 and 6 for val2. This function returns the result of the operation performed by the function 'func'. The function func has two integer parameters. The formal parameters are substituted as 3 for a and 6 for b. since 3 is not equal to 6, a==b returns 0. therefore the function returns 0 which in turn is returned by the function 'process'.

96) void main()
{
static int i=5;
if(--i){
main();
printf("%d ",i);
}
}
Answer:
0 0 0 0
Explanation:
The variable "I" is declared as static, hence memory for I will be allocated for only once, as it encounters the statement. The function main() will be called recursively unless I becomes equal to 0, and since main() is recursively called, so the value of static I ie., 0 will be printed every time the control is returned.

97) void main()
{
int k=ret(sizeof(float));
printf("\n here value is %d",++k);
}
int ret(int ret)
{
ret += 2.5;
return(ret);
}
Answer:
Here value is 7
Explanation:
The int ret(int ret), ie., the function name and the argument name can be the same.
Firstly, the function ret() is called in which the sizeof(float) ie., 4 is passed, after the first expression the value in ret will be 6, as ret is integer hence the value stored in ret will have implicit type conversion from float to int. The ret is returned in main() it is printed after and preincrement.

98) void main()
{
char a[]="12345\0";
int i=strlen(a);
printf("here in 3 %d\n",++i);
}
Answer:
here in 3 6
Explanation:
The char array 'a' will hold the initialized string, whose length will be counted from 0 till the null character. Hence the 'I' will hold the value equal to 5, after the pre-increment in the printf statement, the 6 will be printed.

99) void main()
{
unsigned giveit=-1;
int gotit;
printf("%u ",++giveit);
printf("%u \n",gotit=--giveit);
}
Answer:
0 65535
Explanation:

100) void main()
{
int i;
char a[]="\0";
if(printf("%s\n",a))
printf("Ok here \n");
else
printf("Forget it\n");
}
Answer:
Ok here
Explanation:
Printf will return how many characters does it print. Hence printing a null character returns 1 which makes the if statement true, thus "Ok here" is printed.

101) void main()
{
void *v;
int integer=2;
int *i=&integer;
v=i;
printf("%d",(int*)*v);
}
Answer:
Compiler Error. We cannot apply indirection on type void*.
Explanation:
Void pointer is a generic pointer type. No pointer arithmetic can be done on it. Void pointers are normally used for,
Passing generic pointers to functions and returning such pointers.
As a intermediate pointer type.
Used when the exact pointer type will be known at a later point of time.

102) void main()
{
int i=i++,j=j++,k=k++;
printf(“%d%d%d”,i,j,k);
}
Answer:
Garbage values.
Explanation:
An identifier is available to use in program code from the point of its declaration.
So expressions such as i = i++ are valid statements. The i, j and k are automatic variables and so they contain some garbage value. Garbage in is garbage out (GIGO).

103) void main()
{
static int i=i++, j=j++, k=k++;
printf(“i = %d j = %d k = %d”, i, j, k);
}
Answer:
i = 1 j = 1 k = 1
Explanation:
Since static variables are initialized to zero by default.

104) void main()
{
while(1){
if(printf("%d",printf("%d")))
break;
else
continue;
}
}
Answer:
Garbage values
Explanation:
The inner printf executes first to print some garbage value. The printf returns no of characters printed and this value also cannot be predicted. Still the outer printf prints something and so returns a non-zero value. So it encounters the break statement and comes out of the while statement.

104) main()
{
unsigned int i=10;
while(i-->=0)
printf("%u ",i);

}
Answer:
10 9 8 7 6 5 4 3 2 1 0 65535 65534…..
Explanation:
Since i is an unsigned integer it can never become negative. So the expression i-- >=0 will always be true, leading to an infinite loop.

105) #include<conio.h>
main()
{
int x,y=2,z,a;
if(x=y%2) z=2;
a=2;
printf("%d %d ",z,x);
}
Answer:
Garbage-value 0
Explanation:
The value of y%2 is 0. This value is assigned to x. The condition reduces to if (x) or in other words if(0) and so z goes uninitialized.
Thumb Rule: Check all control paths to write bug free code.

106) main()
{
int a[10];
printf("%d",*a+1-*a+3);
}
Answer:
4
Explanation:
*a and -*a cancels out. The result is as simple as 1 + 3 = 4 !

107) #define prod(a,b) a*b
main()
{
int x=3,y=4;
printf("%d",prod(x+2,y-1));
}
Answer:
10
Explanation:
The macro expands and evaluates to as:
x+2*y-1 => x+(2*y)-1 => 10

108) main()
{
unsigned int i=65000;
while(i++!=0);
printf("%d",i);
}
Answer:
1
Explanation:
Note the semicolon after the while statement. When the value of i becomes 0 it comes out of while loop. Due to post-increment on i the value of i while printing is 1.

109) main()
{
int i=0;
while(+(+i--)!=0)
i-=i++;
printf("%d",i);
}
Answer:
-1
Explanation:
Unary + is the only dummy operator in C. So it has no effect on the expression and now the while loop is, while(i--!=0) which is false and so breaks out of while loop. The value –1 is printed due to the post-decrement operator.

113) main()
{
float f=5,g=10;
enum{i=10,j=20,k=50};
printf("%d\n",++k);
printf("%f\n",f<<2);
printf("%lf\n",f%g);
printf("%lf\n",fmod(f,g));
}
Answer:
Line no 5: Error: Lvalue required
Line no 6: Cannot apply leftshift to float
Line no 7: Cannot apply mod to float
Explanation:
Enumeration constants cannot be modified, so you cannot apply ++.
Bit-wise operators and % operators cannot be applied on float values.
fmod() is to find the modulus values for floats as % operator is for ints.

110) main()
{
int i=10;
void pascal f(int,int,int);
f(i++,i++,i++);
printf(" %d",i);
}
void pascal f(integer :i,integer:j,integer :k)
{
write(i,j,k);
}
Answer:
Compiler error: unknown type integer
Compiler error: undeclared function write
Explanation:
Pascal keyword doesn’t mean that pascal code can be used. It means that the function follows Pascal argument passing mechanism in calling the functions.

111) void pascal f(int i,int j,int k)
{
printf(“%d %d %d”,i, j, k);
}
void cdecl f(int i,int j,int k)
{
printf(“%d %d %d”,i, j, k);
}
main()
{
int i=10;
f(i++,i++,i++);
printf(" %d\n",i);
i=10;
f(i++,i++,i++);
printf(" %d",i);
}
Answer:
10 11 12 13
12 11 10 13
Explanation:
Pascal argument passing mechanism forces the arguments to be called from left to right. cdecl is the normal C argument passing mechanism where the arguments are passed from right to left.

112). What is the output of the program given below

main()
{
signed char i=0;
for(;i>=0;i++) ;
printf("%d\n",i);
}
Answer
-128
Explanation
Notice the semicolon at the end of the for loop. THe initial value of the i is set to 0. The inner loop executes to increment the value from 0 to 127 (the positive range of char) and then it rotates to the negative value of -128. The condition in the for loop fails and so comes out of the for loop. It prints the current value of i that is -128.

113) main()
{
unsigned char i=0;
for(;i>=0;i++) ;
printf("%d\n",i);
}
Answer
infinite loop
Explanation
The difference between the previous question and this one is that the char is declared to be unsigned. So the i++ can never yield negative value and i>=0 never becomes false so that it can come out of the for loop.

114) main()
{
char i=0;
for(;i>=0;i++) ;
printf("%d\n",i);

}
Answer:
Behavior is implementation dependent.
Explanation:
The detail if the char is signed/unsigned by default is implementation dependent. If the implementation treats the char to be signed by default the program will print –128 and terminate. On the other hand if it considers char to be unsigned by default, it goes to infinite loop.
Rule:
You can write programs that have implementation dependent behavior. But dont write programs that depend on such behavior.

115) Is the following statement a declaration/definition. Find what does it mean?
int (*x)[10];
Answer
Definition.
x is a pointer to array of(size 10) integers.

Apply clock-wise rule to find the meaning of this definition.

116). What is the output for the program given below

typedef enum errorType{warning, error, exception,}error;
main()
{
error g1;
g1=1;
printf("%d",g1);
}
Answer
Compiler error: Multiple declaration for error
Explanation
The name error is used in the two meanings. One means that it is a enumerator constant with value 1. The another use is that it is a type name (due to typedef) for enum errorType. Given a situation the compiler cannot distinguish the meaning of error to know in what sense the error is used:
error g1;
g1=error;
// which error it refers in each case?
When the compiler can distinguish between usages then it will not issue error (in pure technical terms, names can only be overloaded in different namespaces).
Note: the extra comma in the declaration,
enum errorType{warning, error, exception,}
is not an error. An extra comma is valid and is provided just for programmer’s convenience.

117) typedef struct error{int warning, error, exception;}error;
main()
{
error g1;
g1.error =1;
printf("%d",g1.error);
}

Answer
1
Explanation
The three usages of name errors can be distinguishable by the compiler at any instance, so valid (they are in different namespaces).
Typedef struct error{int warning, error, exception;}error;
This error can be used only by preceding the error by struct kayword as in:
struct error someError;
typedef struct error{int warning, error, exception;}error;
This can be used only after . (dot) or -> (arrow) operator preceded by the variable name as in :
g1.error =1;
printf("%d",g1.error);
typedef struct error{int warning, error, exception;}error;
This can be used to define variables without using the preceding struct keyword as in:
error g1;
Since the compiler can perfectly distinguish between these three usages, it is perfectly legal and valid.

Note
This code is given here to just explain the concept behind. In real programming don’t use such overloading of names. It reduces the readability of the code. Possible doesn’t mean that we should use it!

118) #ifdef something
int some=0;
#endif

main()
{
int thing = 0;
printf("%d %d\n", some ,thing);
}

Answer:
Compiler error : undefined symbol some
Explanation:
This is a very simple example for conditional compilation. The name something is not already known to the compiler making the declaration
int some = 0;
effectively removed from the source code.

119) #if something == 0
int some=0;
#endif

main()
{
int thing = 0;
printf("%d %d\n", some ,thing);
}

Answer
0 0
Explanation
This code is to show that preprocessor expressions are not the same as the ordinary expressions. If a name is not known the preprocessor treats it to be equal to zero.

120). What is the output for the following program

main()
{
int arr2D[3][3];
printf("%d\n", ((arr2D==* arr2D)&&(* arr2D == arr2D[0])) );
}
Answer
1
Explanation
This is due to the close relation between the arrays and pointers. N dimensional arrays are made up of (N-1) dimensional arrays.
arr2D is made up of a 3 single arrays that contains 3 integers each .

The name arr2D refers to the beginning of all the 3 arrays. *arr2D refers to the start of the first 1D array (of 3 integers) that is the same address as arr2D. So the expression (arr2D == *arr2D) is true (1).
Similarly, *arr2D is nothing but *(arr2D + 0), adding a zero doesn’t change the value/meaning. Again arr2D[0] is the another way of telling *(arr2D + 0). So the expression (*(arr2D + 0) == arr2D[0]) is true (1).
Since both parts of the expression evaluates to true the result is true(1) and the same is printed.

121) void main()
{
if(~0 == (unsigned int)-1)
printf(“You can answer this if you know how values are represented in memory”);
}
Answer
You can answer this if you know how values are represented in memory
Explanation
~ (tilde operator or bit-wise negation operator) operates on 0 to produce all ones to fill the space for an integer. –1 is represented in unsigned value as all 1’s and so both are equal.

122) int swap(int *a,int *b)
{
*a=*a+*b;*b=*a-*b;*a=*a-*b;
}
main()
{
int x=10,y=20;
swap(&x,&y);
printf("x= %d y = %d\n",x,y);
}
Answer
x = 20 y = 10
Explanation
This is one way of swapping two values. Simple checking will help understand this.

123) main()
{
char *p = “ayqm”;
printf(“%c”,++*(p++));
}
Answer:
b

124) main()
{
int i=5;
printf("%d",++i++);
}
Answer:
Compiler error: Lvalue required in function main
Explanation:
++i yields an rvalue. For postfix ++ to operate an lvalue is required.

125) main()
{
char *p = “ayqm”;
char c;
c = ++*p++;
printf(“%c”,c);
}
Answer:
b
Explanation:
There is no difference between the expression ++*(p++) and ++*p++. Parenthesis just works as a visual clue for the reader to see which expression is first evaluated.

126)
int aaa() {printf(“Hi”);}
int bbb(){printf(“hello”);}
iny ccc(){printf(“bye”);}

main()
{
int ( * ptr[3]) ();
ptr[0] = aaa;
ptr[1] = bbb;
ptr[2] =ccc;
ptr[2]();
}
Answer:
bye
Explanation:
int (* ptr[3])() says that ptr is an array of pointers to functions that takes no arguments and returns the type int. By the assignment ptr[0] = aaa; it means that the first function pointer in the array is initialized with the address of the function aaa. Similarly, the other two array elements also get initialized with the addresses of the functions bbb and ccc. Since ptr[2] contains the address of the function ccc, the call to the function ptr[2]() is same as calling ccc(). So it results in printing "bye".

127)
main()
{
int i=5;
printf(“%d”,i=++i ==6);
}

Answer:
1
Explanation:
The expression can be treated as i = (++i==6), because == is of higher precedence than = operator. In the inner expression, ++i is equal to 6 yielding true(1). Hence the result.

128) main()
{
char p[ ]="%d\n";
p[1] = 'c';
printf(p,65);
}
Answer:
A
Explanation:
Due to the assignment p[1] = ‘c’ the string becomes, “%c\n”. Since this string becomes the format string for printf and ASCII value of 65 is ‘A’, the same gets printed.

129) void ( * abc( int, void ( *def) () ) ) ();

Answer::
abc is a ptr to a function which takes 2 parameters .(a). an integer variable.(b). a ptrto a funtion which returns void. the return type of the function is void.
Explanation:
Apply the clock-wise rule to find the result.

130) main()
{
while (strcmp(“some”,”some\0”))
printf(“Strings are not equal\n”);
}
Answer:
No output
Explanation:
Ending the string constant with \0 explicitly makes no difference. So “some” and “some\0” are equivalent. So, strcmp returns 0 (false) hence breaking out of the while loop.

131) main()
{
char str1[] = {‘s’,’o’,’m’,’e’};
char str2[] = {‘s’,’o’,’m’,’e’,’\0’};
while (strcmp(str1,str2))
printf(“Strings are not equal\n”);
}
Answer:
“Strings are not equal”
“Strings are not equal”
….
Explanation:
If a string constant is initialized explicitly with characters, ‘\0’ is not appended automatically to the string. Since str1 doesn’t have null termination, it treats whatever the values that are in the following positions as part of the string until it randomly reaches a ‘\0’. So str1 and str2 are not the same, hence the result.

132) main()
{
int i = 3;
for (;i++=0;) printf(“%d”,i);
}

Answer:
Compiler Error: Lvalue required.
Explanation:
As we know that increment operators return rvalues and hence it cannot appear on the left hand side of an assignment operation.

133) void main()
{
int *mptr, *cptr;
mptr = (int*)malloc(sizeof(int));
printf(“%d”,*mptr);
int *cptr = (int*)calloc(sizeof(int),1);
printf(“%d”,*cptr);
}
Answer:
garbage-value 0
Explanation:
The memory space allocated by malloc is uninitialized, whereas calloc returns the allocated memory space initialized to zeros.

134) void main()
{
static int i;
while(i<=10)
(i>2)?i++:i--;
printf(“%d”, i);
}
Answer:
32767
Explanation:
Since i is static it is initialized to 0. Inside the while loop the conditional operator evaluates to false, executing i--. This continues till the integer value rotates to positive value (32767). The while condition becomes false and hence, comes out of the while loop, printing the i value.

135) main()
{
int i=10,j=20;
j = i, j?(i,j)?i:j:j;
printf("%d %d",i,j);
}

Answer:
10 10
Explanation:
The Ternary operator ( ? : ) is equivalent for if-then-else statement. So the question can be written as:
if(i,j)
{
if(i,j)
j = i;
else
j = j;
}
else
j = j;

136) 1. const char *a;
2. char* const a;
3. char const *a;
-Differentiate the above declarations.

Answer:
1. 'const' applies to char * rather than 'a' ( pointer to a constant char )
*a='F' : illegal
a="Hi" : legal

2. 'const' applies to 'a' rather than to the value of a (constant pointer to char )
*a='F' : legal
a="Hi" : illegal

3. Same as 1.

137) main()
{
int i=5,j=10;
i=i&=j&&10;
printf("%d %d",i,j);
}

Answer:
1 10
Explanation:
The expression can be written as i=(i&=(j&&10)); The inner expression (j&&10) evaluates to 1 because j==10. i is 5. i = 5&1 is 1. Hence the result.

138) main()
{
int i=4,j=7;
j = j || i++ && printf("YOU CAN");
printf("%d %d", i, j);
}

Answer:
4 1
Explanation:
The boolean expression needs to be evaluated only till the truth value of the expression is not known. j is not equal to zero itself means that the expression’s truth value is 1. Because it is followed by || and true || (anything) => true where (anything) will not be evaluated. So the remaining expression is not evaluated and so the value of i remains the same.
Similarly when && operator is involved in an expression, when any of the operands become false, the whole expression’s truth value becomes false and hence the remaining expression will not be evaluated.
false && (anything) => false where (anything) will not be evaluated.

139) main()
{
register int a=2;
printf("Address of a = %d",&a);
printf("Value of a = %d",a);
}
Answer:
Compier Error: '&' on register variable
Rule to Remember:
& (address of ) operator cannot be applied on register variables.

140) main()
{
float i=1.5;
switch(i)
{
case 1: printf("1");
case 2: printf("2");
default : printf("0");
}
}
Answer:
Compiler Error: switch expression not integral
Explanation:
Switch statements can be applied only to integral types.

141) main()
{
extern i;
printf("%d\n",i);
{
int i=20;
printf("%d\n",i);
}
}
Answer:
Linker Error : Unresolved external symbol i
Explanation:
The identifier i is available in the inner block and so using extern has no use in resolving it.

142) main()
{
int a=2,*f1,*f2;
f1=f2=&a;
*f2+=*f2+=a+=2.5;
printf("\n%d %d %d",a,*f1,*f2);
}
Answer:
16 16 16
Explanation:
f1 and f2 both refer to the same memory location a. So changes through f1 and f2 ultimately affects only the value of a.

143) main()
{
char *p="GOOD";
char a[ ]="GOOD";
printf("\n sizeof(p) = %d, sizeof(*p) = %d, strlen(p) = %d", sizeof(p), sizeof(*p), strlen(p));
printf("\n sizeof(a) = %d, strlen(a) = %d", sizeof(a), strlen(a));
}
Answer:
sizeof(p) = 2, sizeof(*p) = 1, strlen(p) = 4
sizeof(a) = 5, strlen(a) = 4
Explanation:
sizeof(p) => sizeof(char*) => 2
sizeof(*p) => sizeof(char) => 1
Similarly,
sizeof(a) => size of the character array => 5
When sizeof operator is applied to an array it returns the sizeof the array and it is not the same as the sizeof the pointer variable. Here the sizeof(a) where a is the character array and the size of the array is 5 because the space necessary for the terminating NULL character should also be taken into account.

144) #define DIM( array, type) sizeof(array)/sizeof(type)
main()
{
int arr[10];
printf(“The dimension of the array is %d”, DIM(arr, int));
}
Answer:
10
Explanation:
The size of integer array of 10 elements is 10 * sizeof(int). The macro expands to sizeof(arr)/sizeof(int) => 10 * sizeof(int) / sizeof(int) => 10.

145) int DIM(int array[])
{
return sizeof(array)/sizeof(int );
}
main()
{
int arr[10];
printf(“The dimension of the array is %d”, DIM(arr));
}
Answer:
1
Explanation:
Arrays cannot be passed to functions as arguments and only the pointers can be passed. So the argument is equivalent to int * array (this is one of the very few places where [] and * usage are equivalent). The return statement becomes, sizeof(int *)/ sizeof(int) that happens to be equal in this case.

146) main()
{
static int a[3][3]={1,2,3,4,5,6,7,8,9};
int i,j;
static *p[]={a,a+1,a+2};
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
printf("%d\t%d\t%d\t%d\n",*(*(p+i)+j),
*(*(j+p)+i),*(*(i+p)+j),*(*(p+j)+i));
}
}
Answer:
1 1 1 1
2 4 2 4
3 7 3 7
4 2 4 2
5 5 5 5
6 8 6 8
7 3 7 3
8 6 8 6
9 9 9 9
Explanation:
*(*(p+i)+j) is equivalent to p[i][j].

147) main()
{
void swap();
int x=10,y=8;
swap(&x,&y);
printf("x=%d y=%d",x,y);
}
void swap(int *a, int *b)
{
*a ^= *b, *b ^= *a, *a ^= *b;
}
Answer:
x=10 y=8
Explanation:
Using ^ like this is a way to swap two variables without using a temporary variable and that too in a single statement.
Inside main(), void swap(); means that swap is a function that may take any number of arguments (not no arguments) and returns nothing. So this doesn’t issue a compiler error by the call swap(&x,&y); that has two arguments.
This convention is historically due to pre-ANSI style (referred to as Kernighan and Ritchie style) style of function declaration. In that style, the swap function will be defined as follows,
void swap()
int *a, int *b
{
*a ^= *b, *b ^= *a, *a ^= *b;
}
where the arguments follow the (). So naturally the declaration for swap will look like, void swap() which means the swap can take any number of arguments.

148) main()
{
int i = 257;
int *iPtr = &i;
printf("%d %d", *((char*)iPtr), *((char*)iPtr+1) );
}
Answer:
1 1
Explanation:
The integer value 257 is stored in the memory as, 00000001 00000001, so the individual bytes are taken by casting it to char * and get printed.

149) main()
{
int i = 258;
int *iPtr = &i;
printf("%d %d", *((char*)iPtr), *((char*)iPtr+1) );
}
Answer:
2 1
Explanation:
The integer value 257 can be represented in binary as, 00000001 00000001. Remember that the INTEL machines are ‘small-endian’ machines. Small-endian means that the lower order bytes are stored in the higher memory addresses and the higher order bytes are stored in lower addresses. The integer value 258 is stored in memory as: 00000001 00000010.

150) main()
{
int i=300;
char *ptr = &i;
*++ptr=2;
printf("%d",i);
}
Answer:
556
Explanation:
The integer value 300 in binary notation is: 00000001 00101100. It is stored in memory (small-endian) as: 00101100 00000001. Result of the expression *++ptr = 2 makes the memory representation as: 00101100 00000010. So the integer corresponding to it is 00000010 00101100 => 556.

151) #include <stdio.h>
main()
{
char * str = "hello";
char * ptr = str;
char least = 127;
while (*ptr++)
least = (*ptr<least ) ?*ptr :least;
printf("%d",least);
}
Answer:
0
Explanation:
After ‘ptr’ reaches the end of the string the value pointed by ‘str’ is ‘\0’. So the value of ‘str’ is less than that of ‘least’. So the value of ‘least’ finally is 0.

152) Declare an array of N pointers to functions returning pointers to functions returning pointers to characters?
Answer:
(char*(*)( )) (*ptr[N])( );

153) main()
{
struct student
{
char name[30];
struct date dob;
}stud;
struct date
{
int day,month,year;
};
scanf("%s%d%d%d", stud.rollno, &student.dob.day, &student.dob.month, &student.dob.year);
}
Answer:
Compiler Error: Undefined structure date
Explanation:
Inside the struct definition of ‘student’ the member of type struct date is given. The compiler doesn’t have the definition of date structure (forward reference is not allowed in C in this case) so it issues an error.

154) main()
{
struct date;
struct student
{
char name[30];
struct date dob;
}stud;
struct date
{
int day,month,year;
};
scanf("%s%d%d%d", stud.rollno, &student.dob.day, &student.dob.month, &student.dob.year);
}
Answer:
Compiler Error: Undefined structure date
Explanation:
Only declaration of struct date is available inside the structure definition of ‘student’ but to have a variable of type struct date the definition of the structure is required.

155) There were 10 records stored in “somefile.dat” but the following program printed 11 names. What went wrong?
void main()
{
struct student
{
char name[30], rollno[6];
}stud;
FILE *fp = fopen(“somefile.dat”,”r”);
while(!feof(fp))
{
fread(&stud, sizeof(stud), 1 , fp);
puts(stud.name);
}
}
Explanation:
fread reads 10 records and prints the names successfully. It will return EOF only when fread tries to read another record and fails reading EOF (and returning EOF). So it prints the last record again. After this only the condition feof(fp) becomes false, hence comes out of the while loop.

156) Is there any difference between the two declarations,
int foo(int *arr[]) and
int foo(int *arr[2])
Answer:
No
Explanation:
Functions can only pass pointers and not arrays. The numbers that are allowed inside the [] is just for more readability. So there is no difference between the two declarations.

157) What is the subtle error in the following code segment?
void fun(int n, int arr[])
{
int *p=0;
int i=0;
while(i++<n)
p = &arr[i];
*p = 0;
}
Answer & Explanation:
If the body of the loop never executes p is assigned no address. So p remains NULL where *p =0 may result in problem (may rise to runtime error “NULL pointer assignment” and terminate the program).

158) What is wrong with the following code?
int *foo()
{
int *s = malloc(sizeof(int)100);
assert(s != NULL);
return s;
}
Answer & Explanation:
assert macro should be used for debugging and finding out bugs. The check s != NULL is for error/exception handling and for that assert shouldn’t be used. A plain if and the corresponding remedy statement has to be given.

159) What is the hidden bug with the following statement?
assert(val++ != 0);
Answer & Explanation:
Assert macro is used for debugging and removed in release version. In assert, the experssion involves side-effects. So the behavior of the code becomes different in case of debug version and the release version thus leading to a subtle bug.
Rule to Remember:
Don’t use expressions that have side-effects in assert statements.

160) void main()
{
int *i = 0x400; // i points to the address 400
*i = 0; // set the value of memory location pointed by i;
}
Answer:
Undefined behavior
Explanation:
The second statement results in undefined behavior because it points to some location whose value may not be available for modification. This type of pointer in which the non-availability of the implementation of the referenced location is known as 'incomplete type'.

161) #define assert(cond) if(!(cond)) \
(fprintf(stderr, "assertion failed: %s, file %s, line %d \n",#cond,\
__FILE__,__LINE__), abort())

void main()
{
int i = 10;
if(i==0)
assert(i < 100);
else
printf("This statement becomes else for if in assert macro");
}
Answer:
No output
Explanation:
The else part in which the printf is there becomes the else for if in the assert macro. Hence nothing is printed.
The solution is to use conditional operator instead of if statement,
#define assert(cond) ((cond)?(0): (fprintf (stderr, "assertion failed: \ %s, file %s, line %d \n",#cond, __FILE__,__LINE__), abort()))

Note:
However this problem of “matching with nearest else” cannot be solved by the usual method of placing the if statement inside a block like this,
#define assert(cond) { \
if(!(cond)) \
(fprintf(stderr, "assertion failed: %s, file %s, line %d \n",#cond,\
__FILE__,__LINE__), abort()) \
}

162) Is the following code legal?
struct a
{
int x;
struct a b;
}
Answer:
No
Explanation:
Is it not legal for a structure to contain a member that is of the same
type as in this case. Because this will cause the structure declaration to be recursive without end.

163) Is the following code legal?
struct a
{
int x;
struct a *b;
}
Answer:
Yes.
Explanation:
*b is a pointer to type struct a and so is legal. The compiler knows, the size of the pointer to a structure even before the size of the structure
is determined(as you know the pointer to any type is of same size). This type of structures is known as ‘self-referencing’ structure.

164) Is the following code legal?
typedef struct a
{
int x;
aType *b;
}aType
Answer:
No
Explanation:
The typename aType is not known at the point of declaring the structure (forward references are not made for typedefs).

165) Is the following code legal?
typedef struct a aType;
struct a
{
int x;
aType *b;
};
Answer:
Yes
Explanation:
The typename aType is known at the point of declaring the structure, because it is already typedefined.

166) Is the following code legal?
void main()
{
typedef struct a aType;
aType someVariable;
struct a
{
int x;
aType *b;
};
}
Answer:
No
Explanation:
When the declaration,
typedef struct a aType;
is encountered body of struct a is not known. This is known as ‘incomplete types’.

167) void main()
{
printf(“sizeof (void *) = %d \n“, sizeof( void *));
printf(“sizeof (int *) = %d \n”, sizeof(int *));
printf(“sizeof (double *) = %d \n”, sizeof(double *));
printf(“sizeof(struct unknown *) = %d \n”, sizeof(struct unknown *));
}
Answer :
sizeof (void *) = 2
sizeof (int *) = 2
sizeof (double *) = 2
sizeof(struct unknown *) = 2
Explanation:
The pointer to any type is of same size.

168) char inputString[100] = {0};
To get string input from the keyboard which one of the following is better?
1) gets(inputString)
2) fgets(inputString, sizeof(inputString), fp)
Answer & Explanation:
The second one is better because gets(inputString) doesn't know the size of the string passed and so, if a very big input (here, more than 100 chars) the charactes will be written past the input string. When fgets is used with stdin performs the same operation as gets but is safe.

169) Which version do you prefer of the following two,
1) printf(“%s”,str); // or the more curt one
2) printf(str);
Answer & Explanation:
Prefer the first one. If the str contains any format characters like %d then it will result in a subtle bug.

170) void main()
{
int i=10, j=2;
int *ip= &i, *jp = &j;
int k = *ip/*jp;
printf(“%d”,k);
}
Answer:
Compiler Error: “Unexpected end of file in comment started in line 5”.
Explanation:
The programmer intended to divide two integers, but by the “maximum munch” rule, the compiler treats the operator sequence / and * as /* which happens to be the starting of comment. To force what is intended by the programmer,
int k = *ip/ *jp;
// give space explicity separating / and *
//or
int k = *ip/(*jp);
// put braces to force the intention
will solve the problem.

171) void main()
{
char ch;
for(ch=0;ch<=127;ch++)
printf(“%c %d \n“, ch, ch);
}
Answer:
Implementaion dependent
Explanation:
The char type may be signed or unsigned by default. If it is signed then ch++ is executed after ch reaches 127 and rotates back to -128. Thus ch is always smaller than 127.

172) Is this code legal?
int *ptr;
ptr = (int *) 0x400;
Answer:
Yes
Explanation:
The pointer ptr will point at the integer in the memory location 0x400.

173) main()
{
char a[4]="HELLO";
printf("%s",a);
}
Answer:
Compiler error: Too many initializers
Explanation:
The array a is of size 4 but the string constant requires 6 bytes to get stored.

174) main()
{
char a[4]="HELL";
printf("%s",a);
}
Answer:
HELL%@!~@!@???@~~!
Explanation:
The character array has the memory just enough to hold the string “HELL” and doesnt have enough space to store the terminating null character. So it prints the HELL correctly and continues to print garbage values till it accidentally comes across a NULL character.

175) main()
{
int a=10,*j;
void *k;
j=k=&a;
j++;
k++;
printf("\n %u %u ",j,k);
}
Answer:
Compiler error: Cannot increment a void pointer
Explanation:
Void pointers are generic pointers and they can be used only when the type is not known and as an intermediate address storage type. No pointer arithmetic can be done on it and you cannot apply indirection operator (*) on void pointers.

176) main()
{
extern int i;
{ int i=20;
{
const volatile unsigned i=30; printf("%d",i);
}
printf("%d",i);
}
printf("%d",i);
}
int i;

177) Printf can be implemented by using __________ list.
Answer:
Variable length argument lists
178) char *someFun()
{
char *temp = “string constant";
return temp;
}
int main()
{
puts(someFun());
}
Answer:
string constant
Explanation:
The program suffers no problem and gives the output correctly because the character constants are stored in code/data area and not allocated in stack, so this doesn’t lead to dangling pointers.

179) char *someFun1()
{
char temp[ ] = “string";
return temp;
}
char *someFun2()
{
char temp[ ] = {‘s’, ‘t’,’r’,’i’,’n’,’g’};
return temp;
}
int main()
{
puts(someFun1());
puts(someFun2());
}
Answer:
Garbage values.
Explanation:

Both the functions suffer from the problem of dangling pointers. In someFun1() temp is a character array and so the space for it is allocated in heap and is initialized with character string “string”. This is created dynamically as the function is called, so is also deleted dynamically on exiting the function so the string data is not available in the calling function main() leading to print some garbage values. The function someFun2() also suffers from the same problem but the problem can be easily identified in this case.

C,C++ Questions Aptitude Part 1

1. Base class has some virtual method and derived class has a method with the same name. If we initialize the base class pointer with derived
object,. calling of that virtual method will result in which method being called?
a. Base method
b. Derived method..
Ans. b
2. For the following C program
#define AREA(x)(3.14*x*x)
main()
{float r1=6.25,r2=2.5,a;
a=AREA(r1);
printf("\n Area of the circle is %f", a);
a=AREA(r2);
printf("\n Area of the circle is %f", a);
}
What is the output?
Ans. Area of the circle is 122.656250
Area of the circle is 19.625000
3. What do the following statements indicate. Explain.
· int(*p)[10]
· int*f()
· int(*pf)()
· int*p[10]
Refer to:
-- Kernighan & Ritchie page no. 122
-- Schaum series page no. 323
4.
void main()
{
int d=5;
printf("%f",d);
}
Ans: Undefined

5.
void main()
{
int i;
for(i=1;i<4,i++)
switch(i)
case 1: printf("%d",i);break;
{
case 2:printf("%d",i);break;
case 3:printf("%d",i);break;
}
switch(i) case 4:printf("%d",i);
}
Ans: 1,2,3,4

6.
void main()
{
char *s="\12345s\n";
printf("%d",sizeof(s));
}
Ans: 6

7.
void main()
{
unsigned i=1; /* unsigned char k= -1 => k=255; */
signed j=-1; /* char k= -1 => k=65535 */
/* unsigned or signed int k= -1 =>k=65535 */
if(i<j)
printf("less");
else
if(i>j)
printf("greater");
else
if(i==j)
printf("equal");
}
Ans: less

8.
void main()
{
float j;
j=1000*1000;
printf("%f",j);
}

1. 1000000
2. Overflow
3. Error
4. None
Ans: 4

9. How do you declare an array of N pointers to functions returning
pointers to functions returning pointers to characters?

Ans: The first part of this question can be answered in at least
three ways:

1. char *(*(*a[N])())();

2. Build the declaration up incrementally, using typedefs:

typedef char *pc; /* pointer to char */
typedef pc fpc(); /* function returning pointer to char */
typedef fpc *pfpc; /* pointer to above */
typedef pfpc fpfpc(); /* function returning... */
typedef fpfpc *pfpfpc; /* pointer to... */
pfpfpc a[N]; /* array of... */

3. Use the cdecl program, which turns English into C and vice
versa:

cdecl> declare a as array of pointer to function returning
pointer to function returning pointer to char
char *(*(*a[])())()

cdecl can also explain complicated declarations, help with
casts, and indicate which set of parentheses the arguments
go in (for complicated function definitions, like the one
above).
Any good book on C should explain how to read these complicated
C declarations "inside out" to understand them ("declaration
mimics use").
The pointer-to-function declarations in the examples above have
not included parameter type information. When the parameters
have complicated types, declarations can *really* get messy.
(Modern versions of cdecl can help here, too.)

10. A structure pointer is defined of the type time . With 3 fields min,sec hours having pointers to intergers.
Write the way to initialize the 2nd element to 10.

11. In the above question an array of pointers is declared.
Write the statement to initialize the 3rd element of the 2 element to 10;

12.
int f()
void main()
{
f(1);
f(1,2);
f(1,2,3);
}
f(int i,int j,int k)
{
printf("%d %d %d",i,j,k);
}

What are the number of syntax errors in the above?

Ans: None.

13.
void main()
{
int i=7;
printf("%d",i++*i++);
}

Ans: 56

14.
#define one 0
#ifdef one
printf("one is defined ");
#ifndef one
printf("one is not defined ");

Ans: "one is defined"

15.
void main()
{
int count=10,*temp,sum=0;
temp=&count;
*temp=20;
temp=∑
*temp=count;
printf("%d %d %d ",count,*temp,sum);
}

Ans: 20 20 20

16. There was question in c working only on unix machine with pattern matching.

14. what is alloca()
Ans : It allocates and frees memory after use/after getting out of scope

17.
main()
{
static i=3;
printf("%d",i--);
return i>0 ? main():0;
}

Ans: 321

18.
char *foo()
{
char result[100]);
strcpy(result,"anything is good");
return(result);
}
void main()
{
char *j;
j=foo()
printf("%s",j);
}

Ans: anything is good.

19.
void main()
{
char *s[]={ "dharma","hewlett-packard","siemens","ibm"};
char **p;
p=s;
printf("%s",++*p);
printf("%s",*p++);
printf("%s",++*p);
}
Ans: "harma" (p->add(dharma) && (*p)->harma)
"harma" (after printing, p->add(hewlett-packard) &&(*p)->harma)
"ewlett-packard"
20. Output of the following program is
main()
{int i=0;
for(i=0;i<20;i++)
{switch(i)
case 0:i+=5;
case 1:i+=2;
case 5:i+=5;
default i+=4;
break;}
printf("%d,",i);
}
}
a) 0,5,9,13,17
b) 5,9,13,17
c) 12,17,22
d) 16,21
e) Syntax error
Ans. (d)
21. What is the ouptut in the following program
main()
{char c=-64;
int i=-32
unsigned int u =-16;
if(c>i)
{printf("pass1,");
if(c<u)
printf("pass2");
else
printf("Fail2");
}
else
printf("Fail1);
if(i<u)
printf("pass2");
else
printf("Fail2")
}
a) Pass1,Pass2
b) Pass1,Fail2
c) Fail1,Pass2
d) Fail1,Fail2
e) None of these
Ans. (c)
22. What will the following program do?
void main()
{
int i;
char a[]="String";
char *p="New Sring";
char *Temp;
Temp=a;
a=malloc(strlen(p) + 1);
strcpy(a,p); //Line number:9//
p = malloc(strlen(Temp) + 1);
strcpy(p,Temp);
printf("(%s, %s)",a,p);
free(p);
free(a);
} //Line number 15//
a) Swap contents of p & a and print:(New string, string)
b) Generate compilation error in line number 8
c) Generate compilation error in line number 5
d) Generate compilation error in line number 7
e) Generate compilation error in line number 1
Ans. (b)
23. In the following code segment what will be the result of the function,
value of x , value of y
{unsigned int x=-1;
int y;
y = ~0;
if(x == y)
printf("same");
else
printf("not same");
}
a) same, MAXINT, -1
b) not same, MAXINT, -MAXINT
c) same , MAXUNIT, -1
d) same, MAXUNIT, MAXUNIT
e) not same, MAXINT, MAXUNIT
Ans. (a)
24. What will be the result of the following program ?
char *gxxx()
{static char xxx[1024];
return xxx;
}
main()
{char *g="string";
strcpy(gxxx(),g);
g = gxxx();
strcpy(g,"oldstring");
printf("The string is : %s",gxxx());
}
a) The string is : string
b) The string is :Oldstring
c) Run time error/Core dump
d) Syntax error during compilation
e) None of these
Ans. (b)
25. Find the output for the following C program
main()
{
char *p1="Name";
char *p2;
p2=(char *)malloc(20);
while(*p2++=*p1++);
printf("%s\n",p2);
}
Ans. An empty string
26. Find the output for the following C program
main()
{
int x=20,y=35;
x = y++ + x++;
y = ++y + ++x;
printf("%d %d\n",x,y);
}
Ans. 57 94
27. Find the output for the following C program
main()
{
int x=5;
printf("%d %d %d\n",x,x<<2,x>>2);
}
Ans. 5 20 1
28 Find the output for the following C program
#define swap1(a,b) a=a+b;b=a-b;a=a-b;
main()
{
int x=5,y=10;
swap1(x,y);
printf("%d %d\n",x,y);
swap2(x,y);
printf("%d %d\n",x,y);
}
int swap2(int a,int b)
{
int temp;
temp=a;
b=a;
a=temp;
return;
}
Ans. 10 5

29 Find the output for the following C program
main()
{
char *ptr = "Ramco Systems";
(*ptr)++;
printf("%s\n",ptr);
ptr++;
printf("%s\n",ptr);
}
Ans. Samco Systems

30 Find the output for the following C program
#include<stdio.h>
main()
{
char s1[]="Ramco";
char s2[]="Systems";
s1=s2;
printf("%s",s1);
}
Ans. Compilation error giving it cannot be an modifiable 'lvalue'

31 Find the output for the following C program
#include<stdio.h>
main()
{
char *p1;
char *p2;
p1=(char *) malloc(25);
p2=(char *) malloc(25);
strcpy(p1,"Ramco");
strcpy(p2,"Systems");
strcat(p1,p2);
printf("%s",p1);
}
Ans. RamcoSystems

32. Find the output for the following C program given that
[1]. The following variable is available in file1.c
static int average_float;
Ans. All the functions in the file1.c can access the variable

33. Find the output for the following C program
# define TRUE 0
some code
while(TRUE)
{
some code
}
Ans. This won't go into the loop as TRUE is defined as 0
34. struct list{
int x;
struct list *next;
}*head;

the struct head.x =100

Is the above assignment to pointer is correct or wrong ?
Ans. Wrong
35.What is the output of the following ?

int i;
i=1;
i=i+2*i++;
printf(%d,i);
Ans. 4
36. FILE *fp1,*fp2;

fp1=fopen("one","w")
fp2=fopen("one","w")
fputc('A',fp1)
fputc('B',fp2)
fclose(fp1)
fclose(fp2)
}

Find the Error, If Any?
Ans. no error. But It will over writes on same file.
37. What are the output(s) for the following ?
38. #include<malloc.h>
char *f()
{char *s=malloc(8);
strcpy(s,"goodbye");
}

main()
{
char *f();
printf("%c",*f()='A'); }

39. #define MAN(x,y) (x)>(y)?(x):(y)
{int i=10;
j=5;
k=0;
k=MAX(i++,++j);
printf(%d %d %d %d,i,j,k);
}
Ans. 10 5 0
40.
void main()
{
int i=7;
printf("%d",i++*i++);
}

Ans: 56

C++ Aptitude Questions Part 2

Note : All the programs are tested under Turbo C++ 3.0, 4.5 and Microsoft VC++ 6.0 compilers.
It is assumed that,
Programs run under Windows environment,
The underlying machine is an x86 based system,
Program is compiled using Turbo C/C++ compiler.
The program output may depend on the information based on this assumptions (for example sizeof(int) == 2 may be assumed).

1) class Sample
{
public:
int *ptr;
Sample(int i)
{
ptr = new int(i);
}
~Sample()
{
delete ptr;
}
void PrintVal()
{
cout << "The value is " << *ptr;
}
};
void SomeFunc(Sample x)
{
cout << "Say i am in someFunc " << endl;
}
int main()
{
Sample s1= 10;
SomeFunc(s1);
s1.PrintVal();
}
Answer:
Say i am in someFunc
Null pointer assignment(Run-time error)
Explanation:
As the object is passed by value to SomeFunc the destructor of the object is called when the control returns from the function. So when PrintVal is called it meets up with ptr that has been freed.The solution is to pass the Sample object by reference to SomeFunc:

void SomeFunc(Sample &x)
{
cout << "Say i am in someFunc " << endl;
}
because when we pass objects by refernece that object is not destroyed. while returning from the function.

Which is the parameter that is added to every non-static member function when it is called?
Answer:
‘this’ pointer

3) class base
{
public:
int bval;
base(){ bval=0;}
};

class deri:public base
{
public:
int dval;
deri(){ dval=1;}
};
void SomeFunc(base *arr,int size)
{
for(int i=0; i<size; i++,arr++)
cout<<arr->bval;
cout<<endl;
}

int main()
{
base BaseArr[5];
SomeFunc(BaseArr,5);
deri DeriArr[5];
SomeFunc(DeriArr,5);
}

Answer:
00000
01010
Explanation:
The function SomeFunc expects two arguments.The first one is a pointer to an array of base class objects and the second one is the sizeof the array.The first call of someFunc calls it with an array of bae objects, so it works correctly and prints the bval of all the objects. When Somefunc is called the second time the argument passed is the pointeer to an array of derived class objects and not the array of base class objects. But that is what the function expects to be sent. So the derived class pointer is promoted to base class pointer and the address is sent to the function. SomeFunc() knows nothing about this and just treats the pointer as an array of base class objects. So when arr++ is met, the size of base class object is taken into consideration and is incremented by sizeof(int) bytes for bval (the deri class objects have bval and dval as members and so is of size >= sizeof(int)+sizeof(int) ).

4) class base
{
public:
void baseFun(){ cout<<"from base"<<endl;}
};
class deri:public base
{
public:
void baseFun(){ cout<< "from derived"<<endl;}
};
void SomeFunc(base *baseObj)
{
baseObj->baseFun();
}
int main()
{
base baseObject;
SomeFunc(&baseObject);
deri deriObject;
SomeFunc(&deriObject);
}
Answer:
from base
from base
Explanation:
As we have seen in the previous case, SomeFunc expects a pointer to a base class. Since a pointer to a derived class object is passed, it treats the argument only as a base class pointer and the corresponding base function is called.

5) class base
{
public:
virtual void baseFun(){ cout<<"from base"<<endl;}
};
class deri:public base
{
public:
void baseFun(){ cout<< "from derived"<<endl;}
};
void SomeFunc(base *baseObj)
{
baseObj->baseFun();
}
int main()
{
base baseObject;
SomeFunc(&baseObject);
deri deriObject;
SomeFunc(&deriObject);
}
Answer:
from base
from derived
Explanation:
Remember that baseFunc is a virtual function. That means that it supports run-time polymorphism. So the function corresponding to the derived class object is called.

void main()
{
int a, *pa, &ra;
pa = &a;
ra = a;
cout <<"a="<<a <<"*pa="<<*pa <<"ra"<<ra ;
}
/*
Answer :
Compiler Error: 'ra',reference must be initialized
Explanation :
Pointers are different from references. One of the main
differences is that the pointers can be both initialized and assigned,
whereas references can only be initialized. So this code issues an error.
*/

const int size = 5;
void print(int *ptr)
{
cout<<ptr[0];
}

void print(int ptr[size])
{
cout<<ptr[0];
}

void main()
{
int a[size] = {1,2,3,4,5};
int *b = new int(size);
print(a);
print(b);
}
/*
Answer:
Compiler Error : function 'void print(int *)' already has a body

Explanation:
Arrays cannot be passed to functions, only pointers (for arrays, base addresses)
can be passed. So the arguments int *ptr and int prt[size] have no difference
as function arguments. In other words, both the functoins have the same signature and
so cannot be overloaded.
*/

class some{
public:
~some()
{
cout<<"some's destructor"<<endl;
}
};

void main()
{
some s;
s.~some();
}
/*
Answer:
some's destructor
some's destructor
Explanation:
Destructors can be called explicitly. Here 's.~some()' explicitly calls the
destructor of 's'. When main() returns, destructor of s is called again,
hence the result.
*/

#include <iostream.h>

class fig2d
{
int dim1;
int dim2;

public:
fig2d() { dim1=5; dim2=6;}

virtual void operator<<(ostream & rhs);
};

void fig2d::operator<<(ostream &rhs)
{
rhs <<this->dim1<<" "<<this->dim2<<" ";
}

/*class fig3d : public fig2d
{
int dim3;
public:
fig3d() { dim3=7;}
virtual void operator<<(ostream &rhs);
};
void fig3d::operator<<(ostream &rhs)
{
fig2d::operator <<(rhs);
rhs<<this->dim3;
}
*/

void main()
{
fig2d obj1;
// fig3d obj2;

obj1 << cout;
// obj2 << cout;
}
/*
Answer :
5 6
Explanation:
In this program, the << operator is overloaded with ostream as argument.
This enables the 'cout' to be present at the right-hand-side. Normally, 'cout'
is implemented as global function, but it doesn't mean that 'cout' is not possible
to be overloaded as member function.
Overloading << as virtual member function becomes handy when the class in which
it is overloaded is inherited, and this becomes available to be overrided. This is as opposed
to global friend functions, where friend's are not inherited.
*/

class opOverload{
public:
bool operator==(opOverload temp);
};

bool opOverload::operator==(opOverload temp){
if(*this == temp ){
cout<<"The both are same objects\n";
return true;
}
else{
cout<<"The both are different\n";
return false;
}
}

void main(){
opOverload a1, a2;
a1= =a2;
}

Answer :
Runtime Error: Stack Overflow
Explanation :
Just like normal functions, operator functions can be called recursively. This program just illustrates that point, by calling the operator == function recursively, leading to an infinite loop.

class complex{
double re;
double im;
public:
complex() : re(1),im(0.5) {}
bool operator==(complex &rhs);
operator int(){}
};

bool complex::operator == (complex &rhs){
if((this->re == rhs.re) && (this->im == rhs.im))
return true;
else
return false;
}

int main(){
complex c1;
cout<< c1;
}

Answer : Garbage value

Explanation:
The programmer wishes to print the complex object using output
re-direction operator,which he has not defined for his lass.But the compiler instead of giving an error sees the conversion function
and converts the user defined object to standard object and prints
some garbage value.

class complex{
double re;
double im;
public:
complex() : re(0),im(0) {}
complex(double n) { re=n,im=n;};
complex(int m,int n) { re=m,im=n;}
void print() { cout<<re; cout<<im;}
};

void main(){
complex c3;
double i=5;
c3 = i;
c3.print();
}

Answer:
5,5
Explanation:
Though no operator= function taking complex, double is defined, the double on the rhs is converted into a temporary object using the single argument constructor taking double and assigned to the lvalue.

void main()
{
int a, *pa, &ra;
pa = &a;
ra = a;
cout <<"a="<<a <<"*pa="<<*pa <<"ra"<<ra ;
}

Answer :
Compiler Error: 'ra',reference must be initialized
Explanation :
Pointers are different from references. One of the main
differences is that the pointers can be both initialized and assigned,
whereas references can only be initialized. So this code issues an error.

Try it Yourself

1) Determine the output of the 'C++' Codelet.
class base
{
public :
out()
{
cout<<"base ";
}
};
class deri{
public : out()
{
cout<<"deri ";
}
};
void main()
{ deri dp[3];
base *bp = (base*)dp;
for (int i=0; i<3;i++)
(bp++)->out();
}

Justify the use of virtual constructors and destructors in C++.

Each C++ object possesses the 4 member fns,(which can be declared by the programmer explicitly or by the implementation if they are not available). What are those 4 functions?

What is wrong with this class declaration?
class something
{
char *str;
public:
something(){
st = new char[10]; }
~something()
{
delete str;
}
};

5) Inheritance is also known as -------- relationship. Containership as ________ relationship.

6) When is it necessary to use member-wise initialization list (also known as header initialization list) in C++?

7) Which is the only operator in C++ which can be overloaded but NOT inherited.

8) Is there anything wrong with this C++ class declaration?
class temp
{
int value1;
mutable int value2;
public :
void fun(int val)
const{
((temp*) this)->value1 = 10;
value2 = 10;
}
};
1. What is a modifier?
Answer:
A modifier, also called a modifying function is a member function that changes the value of at least one data member. In other words, an operation that modifies the state of an object. Modifiers are also known as ‘mutators’.

2. What is an accessor?
Answer:
An accessor is a class operation that does not modify the state of an object. The accessor functions need to be declared as const operations

3. Differentiate between a template class and class template.
Answer:
Template class:
A generic definition or a parameterized class not instantiated until the client provides the needed information. It’s jargon for plain templates.
Class template:
A class template specifies how individual classes can be constructed much like the way a class specifies how individual objects can be constructed. It’s jargon for plain classes.

4. When does a name clash occur?
Answer:
A name clash occurs when a name is defined in more than one place. For example., two different class libraries could give two different classes the same name. If you try to use many class libraries at the same time, there is a fair chance that you will be unable to compile or link the program because of name clashes.

5. Define namespace.
Answer:
It is a feature in c++ to minimize name collisions in the global name space. This namespace keyword assigns a distinct name to a library that allows other libraries to use the same identifier names without creating any name collisions. Furthermore, the compiler uses the namespace signature for differentiating the definitions.

6. What is the use of ‘using’ declaration.
Answer:
A using declaration makes it possible to use a name from a namespace without the scope operator.

7. What is an Iterator class?
Answer:
A class that is used to traverse through the objects maintained by a container class. There are five categories of iterators:
input iterators,
output iterators,
forward iterators,
bidirectional iterators,
random access.
An iterator is an entity that gives access to the contents of a container object without violating encapsulation constraints. Access to the contents is granted on a one-at-a-time basis in order. The order can be storage order (as in lists and queues) or some arbitrary order (as in array indices) or according to some ordering relation (as in an ordered binary tree). The iterator is a construct, which provides an interface that, when called, yields either the next element in the container, or some value denoting the fact that there are no more elements to examine. Iterators hide the details of access to and update of the elements of a container class.
The simplest and safest iterators are those that permit read-only access to the contents of a container class. The following code fragment shows how an iterator might appear in code:
cont_iter:=new cont_iterator();
x:=cont_iter.next();
while x/=none do
...
s(x);
...
x:=cont_iter.next();
end;
In this example, cont_iter is the name of the iterator. It is created on the first line by instantiation of cont_iterator class, an iterator class defined to iterate over some container class, cont. Succesive elements from the container are carried to x. The loop terminates when x is bound to some empty value. (Here, none)In the middle of the loop, there is s(x) an operation on x, the current element from the container. The next element of the container is obtained at the bottom of the loop.

9. List out some of the OODBMS available.
Answer:
GEMSTONE/OPAL of Gemstone systems.
ONTOS of Ontos.
Objectivity of Objectivity inc.
Versant of Versant object technology.
Object store of Object Design.
ARDENT of ARDENT software.
POET of POET software.

10. List out some of the object-oriented methodologies.
Answer:
Object Oriented Development (OOD) (Booch 1991,1994).
Object Oriented Analysis and Design (OOA/D) (Coad and Yourdon 1991).
Object Modelling Techniques (OMT) (Rumbaugh 1991).
Object Oriented Software Engineering (Objectory) (Jacobson 1992).
Object Oriented Analysis (OOA) (Shlaer and Mellor 1992).
The Fusion Method (Coleman 1991).

11. What is an incomplete type?
Answer:
Incomplete types refers to pointers in which there is non availability of the implementation of the referenced location or it points to some location whose value is not available for modification.
Example:
int *i=0x400 // i points to address 400
*i=0; //set the value of memory location pointed by i.
Incomplete types are otherwise called uninitialized pointers.

12. What is a dangling pointer?
Answer:
A dangling pointer arises when you use the address of an object after its lifetime is over.
This may occur in situations like returning addresses of the automatic variables from a function or using the address of the memory block after it is freed.

13. Differentiate between the message and method.
Answer:
Message Method
Objects communicate by sending messages Provides response to a message.
to each other.
A message is sent to invoke a method. It is an implementation of an operation.

14. What is an adaptor class or Wrapper class?
Answer:
A class that has no functionality of its own. Its member functions hide the use of a third party software component or an object with the non-compatible interface or a non- object- oriented implementation.

15. What is a Null object?
Answer:
It is an object of some class whose purpose is to indicate that a real object of that class does not exist. One common use for a null object is a return value from a member function that is supposed to return an object with some specified properties but cannot find such an object.

16. What is class invariant?
Answer:
A class invariant is a condition that defines all valid states for an object. It is a logical condition to ensure the correct working of a class. Class invariants must hold when an object is created, and they must be preserved under all operations of the class. In particular all class invariants are both preconditions and post-conditions for all operations or member functions of the class.

17. What do you mean by Stack unwinding?
Answer:
It is a process during exception handling when the destructor is called for all local objects between the place where the exception was thrown and where it is caught.

18. Define precondition and post-condition to a member function.
Answer:
Precondition:
A precondition is a condition that must be true on entry to a member function. A class is used correctly if preconditions are never false. An operation is not responsible for doing anything sensible if its precondition fails to hold.
For example, the interface invariants of stack class say nothing about pushing yet another element on a stack that is already full. We say that isful() is a precondition of the push operation.

Post-condition:
A post-condition is a condition that must be true on exit from a member function if the precondition was valid on entry to that function. A class is implemented correctly if post-conditions are never false.
For example, after pushing an element on the stack, we know that isempty() must necessarily hold. This is a post-condition of the push operation.

19. What are the conditions that have to be met for a condition to be an invariant of the class?
Answer:
The condition should hold at the end of every constructor.
The condition should hold at the end of every mutator(non-const) operation.

20. What are proxy objects?
Answer:
Objects that stand for other objects are called proxy objects or surrogates.
Example:
template<class T>
class Array2D
{
public:
class Array1D
{
public:
T& operator[] (int index);
const T& operator[] (int index) const;
...
};
Array1D operator[] (int index);
const Array1D operator[] (int index) const;
...
};

The following then becomes legal:
Array2D<float>data(10,20);
........
cout<<data[3][6]; // fine

Here data[3] yields an Array1D object and the operator [] invocation on that object yields the float in position(3,6) of the original two dimensional array. Clients of the Array2D class need not be aware of the presence of the Array1D class. Objects of this latter class stand for one-dimensional array objects that, conceptually, do not exist for clients of Array2D. Such clients program as if they were using real, live, two-dimensional arrays. Each Array1D object stands for a one-dimensional array that is absent from a conceptual model used by the clients of Array2D. In the above example, Array1D is a proxy class. Its instances stand for one-dimensional arrays that, conceptually, do not exist.

21. Name some pure object oriented languages.
Answer:
Smalltalk,
Java,
Eiffel,
Sather.

22. Name the operators that cannot be overloaded.
Answer:
sizeof . .* .-> :: ?:

23. What is a node class?
Answer:
A node class is a class that,
relies on the base class for services and implementation,
provides a wider interface to te users than its base class,
relies primarily on virtual functions in its public interface
depends on all its direct and indirect base class
can be understood only in the context of the base class
can be used as base for further derivation
can be used to create objects.
A node class is a class that has added new services or functionality beyond the services inherited from its base class.

24. What is an orthogonal base class?
Answer:
If two base classes have no overlapping methods or data they are said to be independent of, or orthogonal to each other. Orthogonal in the sense means that two classes operate in different dimensions and do not interfere with each other in any way. The same derived class may inherit such classes with no difficulty.

25. What is a container class? What are the types of container classes?
Answer:
A container class is a class that is used to hold objects in memory or external storage. A container class acts as a generic holder. A container class has a predefined behavior and a well-known interface. A container class is a supporting class whose purpose is to hide the topology used for maintaining the list of objects in memory. When a container class contains a group of mixed objects, the container is called a heterogeneous container; when the container is holding a group of objects that are all the same, the container is called a homogeneous container.

26. What is a protocol class?
Answer:
An abstract class is a protocol class if:
it neither contains nor inherits from classes that contain member data, non-virtual functions, or private (or protected) members of any kind.
it has a non-inline virtual destructor defined with an empty implementation,
all member functions other than the destructor including inherited functions, are declared pure virtual functions and left undefined.

27. What is a mixin class?
Answer:
A class that provides some but not all of the implementation for a virtual base class is often called mixin. Derivation done just for the purpose of redefining the virtual functions in the base classes is often called mixin inheritance. Mixin classes typically don't share common bases.

28. What is a concrete class?
Answer:
A concrete class is used to define a useful object that can be instantiated as an automatic variable on the program stack. The implementation of a concrete class is defined. The concrete class is not intended to be a base class and no attempt to minimize dependency on other classes in the implementation or behavior of the class.

29.What is the handle class?
Answer:
A handle is a class that maintains a pointer to an object that is programmatically accessible through the public interface of the handle class.
Explanation:
In case of abstract classes, unless one manipulates the objects of these classes through pointers and references, the benefits of the virtual functions are lost. User code may become dependent on details of implementation classes because an abstract type cannot be allocated statistically or on the stack without its size being known. Using pointers or references implies that the burden of memory management falls on the user. Another limitation of abstract class object is of fixed size. Classes however are used to represent concepts that require varying amounts of storage to implement them.
A popular technique for dealing with these issues is to separate what is used as a single object in two parts: a handle providing the user interface and a representation holding all or most of the object's state. The connection between the handle and the representation is typically a pointer in the handle. Often, handles have a bit more data than the simple representation pointer, but not much more. Hence the layout of the handle is typically stable, even when the representation changes and also that handles are small enough to move around relatively freely so that the user needn’t use the pointers and the references.

30. What is an action class?
Answer:
The simplest and most obvious way to specify an action in C++ is to write a function. However, if the action has to be delayed, has to be transmitted 'elsewhere' before being performed, requires its own data, has to be combined with other actions, etc then it often becomes attractive to provide the action in the form of a class that can execute the desired action and provide other services as well. Manipulators used with iostreams is an obvious example.
Explanation:
A common form of action class is a simple class containing just one virtual function.
class Action
{
public:
virtual int do_it( int )=0;
virtual ~Action( );
}
Given this, we can write code say a member that can store actions for later execution without using pointers to functions, without knowing anything about the objects involved, and without even knowing the name of the operation it invokes. For example:
class write_file : public Action
{
File& f;
public:
int do_it(int)
{
return fwrite( ).suceed( );
}
};
class error_message: public Action
{
response_box db(message.cstr( ),"Continue","Cancel","Retry");
switch (db.getresponse( ))
{
case 0: return 0;
case 1: abort();
case 2: current_operation.redo( );return 1;
}
};

A user of the Action class will be completely isolated from any knowledge of derived classes such as write_file and error_message.

31. When can you tell that a memory leak will occur?
Answer:
A memory leak occurs when a program loses the ability to free a block of dynamically allocated memory.

32.What is a parameterized type?
Answer:
A template is a parameterized construct or type containing generic code that can use or manipulate any type. It is called parameterized because an actual type is a parameter of the code body. Polymorphism may be achieved through parameterized types. This type of polymorphism is called parameteric polymorphism. Parameteric polymorphism is the mechanism by which the same code is used on different types passed as parameters.

33. Differentiate between a deep copy and a shallow copy?
Answer:
Deep copy involves using the contents of one object to create another instance of the same class. In a deep copy, the two objects may contain ht same information but the target object will have its own buffers and resources. the destruction of either object will not affect the remaining object. The overloaded assignment operator would create a deep copy of objects.
Shallow copy involves copying the contents of one object into another instance of the same class thus creating a mirror image. Owing to straight copying of references and pointers, the two objects will share the same externally contained contents of the other object to be unpredictable.
Explanation:
Using a copy constructor we simply copy the data values member by member. This method of copying is called shallow copy. If the object is a simple class, comprised of built in types and no pointers this would be acceptable. This function would use the values and the objects and its behavior would not be altered with a shallow copy, only the addresses of pointers that are members are copied and not the value the address is pointing to. The data values of the object would then be inadvertently altered by the function. When the function goes out of scope, the copy of the object with all its data is popped off the stack.
If the object has any pointers a deep copy needs to be executed. With the deep copy of an object, memory is allocated for the object in free store and the elements pointed to are copied. A deep copy is used for objects that are returned from a function.

34. What is an opaque pointer?
Answer:
A pointer is said to be opaque if the definition of the type to which it points to is not included in the current translation unit. A translation unit is the result of merging an implementation file with all its headers and header files.

35. What is a smart pointer?
Answer:
A smart pointer is an object that acts, looks and feels like a normal pointer but offers more functionality. In C++, smart pointers are implemented as template classes that encapsulate a pointer and override standard pointer operators. They have a number of advantages over regular pointers. They are guaranteed to be initialized as either null pointers or pointers to a heap object. Indirection through a null pointer is checked. No delete is ever necessary. Objects are automatically freed when the last pointer to them has gone away. One significant problem with these smart pointers is that unlike regular pointers, they don't respect inheritance. Smart pointers are unattractive for polymorphic code. Given below is an example for the implementation of smart pointers.
Example:
template <class X>
class smart_pointer
{
public:
smart_pointer(); // makes a null pointer
smart_pointer(const X& x) // makes pointer to copy of x

X& operator *( );
const X& operator*( ) const;
X* operator->() const;

smart_pointer(const smart_pointer <X> &);
const smart_pointer <X> & operator =(const smart_pointer<X>&);
~smart_pointer();
private:
//...
};
This class implement a smart pointer to an object of type X. The object itself is located on the heap. Here is how to use it:
smart_pointer <employee> p= employee("Harris",1333);
Like other overloaded operators, p will behave like a regular pointer,
cout<<*p;
p->raise_salary(0.5);

36. What is reflexive association?
Answer:
The 'is-a' is called a reflexive association because the reflexive association permits classes to bear the is-a association not only with their super-classes but also with themselves. It differs from a 'specializes-from' as 'specializes-from' is usually used to describe the association between a super-class and a sub-class. For example:
Printer is-a printer.

37. What is slicing?
Answer:
Slicing means that the data added by a subclass are discarded when an object of the subclass is passed or returned by value or from a function expecting a base class object.
Explanation:
Consider the following class declaration:
class base
{
...
base& operator =(const base&);
base (const base&);
}
void fun( )
{
base e=m;
e=m;
}
As base copy functions don't know anything about the derived only the base part of the derived is copied. This is commonly referred to as slicing. One reason to pass objects of classes in a hierarchy is to avoid slicing. Other reasons are to preserve polymorphic behavior and to gain efficiency.

38. What is name mangling?
Answer:
Name mangling is the process through which your c++ compilers give each function in your program a unique name. In C++, all programs have at-least a few functions with the same name. Name mangling is a concession to the fact that linker always insists on all function names being unique.
Example:
In general, member names are made unique by concatenating the name of the member with that of the class e.g. given the declaration:
class Bar
{
public:
int ival;
...
};
ival becomes something like:
// a possible member name mangling
ival__3Bar
Consider this derivation:
class Foo : public Bar
{
public:
int ival;
...
}
The internal representation of a Foo object is the concatenation of its base and derived class members.
// Pseudo C++ code
// Internal representation of Foo
class Foo
{
public:
int ival__3Bar;
int ival__3Foo;
...
};
Unambiguous access of either ival members is achieved through name mangling. Member functions, because they can be overloaded, require an extensive mangling to provide each with a unique name. Here the compiler generates the same name for the two overloaded instances(Their argument lists make their instances unique).

39. What are proxy objects?
Answer:
Objects that points to other objects are called proxy objects or surrogates. Its an object that provides the same interface as its server object but does not have any functionality. During a method invocation, it routes data to the true server object and sends back the return value to the object.
40. Differentiate between declaration and definition in C++.
Answer:
A declaration introduces a name into the program; a definition provides a unique description of an entity (e.g. type, instance, and function). Declarations can be repeated in a given scope, it introduces a name in a given scope. There must be exactly one definition of every object, function or class used in a C++ program.
A declaration is a definition unless:
it declares a function without specifying its body,
it contains an extern specifier and no initializer or function body,
it is the declaration of a static class data member without a class definition,
it is a class name definition,
it is a typedef declaration.
A definition is a declaration unless:
it defines a static class data member,
it defines a non-inline member function.

41. What is cloning?
Answer:
An object can carry out copying in two ways i.e. it can set itself to be a copy of another object, or it can return a copy of itself. The latter process is called cloning.

42. Describe the main characteristics of static functions.
Answer:
The main characteristics of static functions include,
It is without the a this pointer,
It can't directly access the non-static members of its class
It can't be declared const, volatile or virtual.
It doesn't need to be invoked through an object of its class, although for convenience, it may.

43. Will the inline function be compiled as the inline function always? Justify.
Answer:
An inline function is a request and not a command. Hence it won't be compiled as an inline function always.
Explanation:
Inline-expansion could fail if the inline function contains loops, the address of an inline function is used, or an inline function is called in a complex expression. The rules for inlining are compiler dependent.

44. Define a way other than using the keyword inline to make a function inline.
Answer:
The function must be defined inside the class.

45. How can a '::' operator be used as unary operator?
Answer:
The scope operator can be used to refer to members of the global namespace. Because the global namespace doesn’t have a name, the notation :: member-name refers to a member of the global namespace. This can be useful for referring to members of global namespace whose names have been hidden by names declared in nested local scope. Unless we specify to the compiler in which namespace to search for a declaration, the compiler simple searches the current scope, and any scopes in which the current scope is nested, to find the declaration for the name.

46. What is placement new?
Answer:
When you want to call a constructor directly, you use the placement new. Sometimes you have some raw memory that's already been allocated, and you need to construct an object in the memory you have. Operator new's special version placement new allows you to do it.
class Widget
{
public :
Widget(int widgetsize);
...
Widget* Construct_widget_int_buffer(void *buffer,int widgetsize)
{
return new(buffer) Widget(widgetsize);
}
};
This function returns a pointer to a Widget object that's constructed within the buffer passed to the function. Such a function might be useful for applications using shared memory or memory-mapped I/O, because objects in such applications must be placed at specific addresses or in memory allocated by special routines.

OOAD

What do you mean by analysis and design?
Analysis:
Basically, it is the process of determining what needs to be done before how it should be done. In order to accomplish this, the developer refers the existing systems and documents. So, simply it is an art of discovery.
Design:
It is the process of adopting/choosing the one among the many, which best accomplishes the users needs. So, simply, it is compromising mechanism.

What are the steps involved in designing?
Before getting into the design the designer should go through the SRS prepared by the System Analyst.
The main tasks of design are Architectural Design and Detailed Design.
In Architectural Design we find what are the main modules in the problem domain.
In Detailed Design we find what should be done within each module.

What are the main underlying concepts of object orientation?
Objects, messages, class, inheritance and polymorphism are the main concepts of object orientation.

What do u meant by "SBI" of an object?
SBI stands for State, Behavior and Identity. Since every object has the above three.
State:
It is just a value to the attribute of an object at a particular time.
Behaviour:
It describes the actions and their reactions of that object.
Identity:
An object has an identity that characterizes its own existence. The identity makes it possible to distinguish any object in an unambiguous way, and independently from its state.

Differentiate persistent & non-persistent objects?
Persistent refers to an object's ability to transcend time or space. A persistent object stores/saves its state in a permanent storage system with out losing the information represented by the object.
A non-persistent object is said to be transient or ephemeral. By default objects are considered as non-persistent.

What do you meant by active and passive objects?
Active objects are one which instigate an interaction which owns a thread and they are responsible for handling control to other objects. In simple words it can be referred as client.
Passive objects are one, which passively waits for the message to be processed. It waits for another object that requires its services. In simple words it can be referred as server.

Diagram:
client server
(Active) (Passive)

What is meant by software development method?
Software development method describes how to model and build software systems in a reliable and reproducible way. To put it simple, methods that are used to represent ones' thinking using graphical notations.

What are models and meta models?
Model:
It is a complete description of something (i.e. system).
Meta model:
It describes the model elements, syntax and semantics of the notation that allows their manipulation.

What do you meant by static and dynamic modeling?
Static modeling is used to specify structure of the objects that exist in the problem domain. These are expressed using class, object and USECASE diagrams.
But Dynamic modeling refers representing the object interactions during runtime. It is represented by sequence, activity, collaboration and statechart diagrams.

How to represent the interaction between the modeling elements?
Model element is just a notation to represent (Graphically) the entities that exist in the problem domain. e.g. for modeling element is class notation, object notation etc.
Relationships are used to represent the interaction between the modeling elements.
The following are the Relationships.

Association: Its' just a semantic connection two classes.
e.g.:

Aggregation: Its' the relationship between two classes which are related in the fashion that master and slave. The master takes full rights than the slave. Since the slave works under the master. It is represented as line with diamond in the master area.
ex:
car contains wheels, etc.

car

Containment: This relationship is applied when the part contained with in the whole part, dies when the whole part dies.
It is represented as darked diamond at the whole part.
example:
class A{
//some code
};

class B
{
A aa; // an object of class A;
// some code for class B;
};
In the above example we see that an object of class A is instantiated with in the class B. so the object class A dies when the object class B dies.we can represnt it in diagram like this.

Generalization: This relationship used when we want represents a class, which captures the common states of objects of different classes. It is represented as arrow line pointed at the class, which has captured the common states.

Dependency: It is the relationship between dependent and independent classes. Any change in the independent class will affect the states of the dependent class.
DIAGRAM:
class A class B

Why generalization is very strong?
Even though Generalization satisfies Structural, Interface, Behaviour properties. It is mathematically very strong, as it is Antisymmetric and Transitive.
Antisymmetric: employee is a person, but not all persons are employees. Mathematically all As’ are B, but all Bs’ not A.
Transitive: A=>B, B=>c then A=>c.
A. Salesman.
B. Employee.
C. Person.
Note: All the other relationships satisfy all the properties like Structural properties, Interface properties, Behaviour properties.

Differentiate Aggregation and containment?
Aggregation is the relationship between the whole and a part. We can add/subtract some properties in the part (slave) side. It won't affect the whole part.
Best example is Car, which contains the wheels and some extra parts. Even though the parts are not there we can call it as car.
But, in the case of containment the whole part is affected when the part within that got affected. The human body is an apt example for this relationship. When the whole body dies the parts (heart etc) are died.

Can link and Association applied interchangeably?
No, You cannot apply the link and Association interchangeably. Since link is used represent the relationship between the two objects.
But Association is used represent the relationship between the two classes.
link :: student:Abhilash course:MCA
Association:: student course

what is meant by "method-wars"?
Before 1994 there were different methodologies like Rumbaugh, Booch, Jacobson, Meyer etc who followed their own notations to model the systems. The developers were in a dilemma to choose the method which best accomplishes their needs. This particular span was called as "method-wars"

Whether unified method and unified modeling language are same or different?
Unified method is convergence of the Rumbaugh and Booch.
Unified modeling lang. is the fusion of Rumbaugh, Booch and Jacobson as well as Betrand Meyer (whose contribution is "sequence diagram"). Its' the superset of all the methodologies.

Who were the three famous amigos and what was their contribution to the object community?
The Three amigos namely,
James Rumbaugh (OMT): A veteran in analysis who came up with an idea about the objects and their Relationships (in particular Associations).
Grady Booch: A veteran in design who came up with an idea about partitioning of systems into subsystems.

Ivar Jacobson (Objectory): The father of USECASES, who described about the user and system interaction.

Differentiate the class representation of Booch, Rumbaugh and UML?
If you look at the class representaiton of Rumbaugh and UML, It is some what similar and both are very easy to draw.
Representation: OMT UML.
Diagram:

Booch: In this method classes are represented as "Clouds" which are not very easy to draw as for as the developer's view is concern.
Diagram:

What is an USECASE? Why it is needed?
A Use Case is a description of a set of sequence of actions that a system performs that yields an observable result of value to a particular action.
In SSAD process <=> In OOAD USECASE. It is represented elliptically.
Representation:

Who is an Actor?
An Actor is someone or something that must interact with the system.In addition to that an Actor initiates the process(that is USECASE).
It is represented as a stickman like this.
Diagram:

What is guard condition?
Guard condition is one, which acts as a firewall. The access from a particular object can be made only when the particular condition is met.
For Example,
customer check customer number ATM.
Here the object on the customer accesses the ATM facility only when the guard condition is met.

Differentiate the following notations?
I: :obj1 :obj2

II: :obj1 :obj2

In the above representation I, obj1 sends message to obj2. But in the case of II the data is transferred from obj1 to obj2.

USECASE is an implementation independent notation. How will the designer give the implementation details of a particular USECASE to the programmer?
This can be accomplished by specifying the relationship called "refinement” which talks about the two different abstraction of the same thing.
Or example,

calculate pay calculate

class1 class2 class3

Suppose a class acts an Actor in the problem domain, how to represent it in the static model?
In this scenario you can use “stereotype”. Since stereotype is just a string that gives extra semantic to the particular entity/model element. It is given with in the << >>.

class A
<< Actor>>
attributes

methods.

Why does the function arguments are called as "signatures"?
The arguments distinguish functions with the same name (functional polymorphism). The name alone does not necessarily identify a unique function. However, the name and its arguments (signatures) will uniquely identify a function.
In real life we see suppose, in class there are two guys with same name, but they can be easily identified by their signatures. The same concept is applied here.
ex:
class person
{
public:
char getsex();
void setsex(char);
void setsex(int);
};
In the above example we see that there is a function setsex() with same name but with different signature.

Relational Database management system or Data base Management System Aptitude

What is database?
A database is a logically coherent collection of data with some inherent meaning, representing some aspect of real world and which is designed, built and populated with data for a specific purpose.

What is DBMS?
It is a collection of programs that enables user to create and maintain a database. In other words it is general-purpose software that provides the users with the processes of defining, constructing and manipulating the database for various applications.

What is a Database system?
The database and DBMS software together is called as Database system.

Advantages of DBMS?
Redundancy is controlled.
Unauthorised access is restricted.
Providing multiple user interfaces.
Enforcing integrity constraints.
Providing backup and recovery.

Disadvantage in File Processing System?
Data redundancy & inconsistency.
Difficult in accessing data.
Data isolation.
Data integrity.
Concurrent access is not possible.
Security Problems.

Describe the three levels of data abstraction?
The are three levels of abstraction:
Physical level: The lowest level of abstraction describes how data are stored.
Logical level: The next higher level of abstraction, describes what data are stored in database and what relationship among those data.
View level: The highest level of abstraction describes only part of entire database.
Define the "integrity rules"
There are two Integrity rules.
Entity Integrity: States that “Primary key cannot have NULL value”
Referential Integrity: States that “Foreign Key can be either a NULL value or should be Primary Key value of other relation.

What is extension and intension?
Extension -
It is the number of tuples present in a table at any instance. This is time dependent.
Intension -
It is a constant value that gives the name, structure of table and the constraints laid on it.

What is System R? What are its two major subsystems?
System R was designed and developed over a period of 1974-79 at IBM San Jose Research Center. It is a prototype and its purpose was to demonstrate that it is possible to build a Relational System that can be used in a real life environment to solve real life problems, with performance at least comparable to that of existing system.
Its two subsystems are
Research Storage
System Relational Data System.

How is the data structure of System R different from the relational structure?
Unlike Relational systems in System R
Domains are not supported
Enforcement of candidate key uniqueness is optional
Enforcement of entity integrity is optional
Referential integrity is not enforced

What is Data Independence?
Data independence means that “the application is independent of the storage structure and access strategy of data”. In other words, The ability to modify the schema definition in one level should not affect the schema definition in the next higher level.
Two types of Data Independence:
Physical Data Independence: Modification in physical level should not affect the logical level.
Logical Data Independence: Modification in logical level should affect the view level.
NOTE: Logical Data Independence is more difficult to achieve

What is a view? How it is related to data independence?
A view may be thought of as a virtual table, that is, a table that does not really exist in its own right but is instead derived from one or more underlying base table. In other words, there is no stored file that direct represents the view instead a definition of view is stored in data dictionary.
Growth and restructuring of base tables is not reflected in views. Thus the view can insulate users from the effects of restructuring and growth in the database. Hence accounts for logical data independence.

What is Data Model?
A collection of conceptual tools for describing data, data relationships data semantics and constraints.

What is E-R model?
This data model is based on real world that consists of basic objects called entities and of relationship among these objects. Entities are described in a database by a set of attributes.

What is Object Oriented model?
This model is based on collection of objects. An object contains values stored in instance variables with in the object. An object also contains bodies of code that operate on the object. These bodies of code are called methods. Objects that contain same types of values and the same methods are grouped together into classes.

What is an Entity?
It is a 'thing' in the real world with an independent existence.

What is an Entity type?
It is a collection (set) of entities that have same attributes.

What is an Entity set?
It is a collection of all entities of particular entity type in the database.

What is an Extension of entity type?
The collections of entities of a particular entity type are grouped together into an entity set.

What is Weak Entity set?
An entity set may not have sufficient attributes to form a primary key, and its primary key compromises of its partial key and primary key of its parent entity, then it is said to be Weak Entity set.

What is an attribute?
It is a particular property, which describes the entity.

What is a Relation Schema and a Relation?
A relation Schema denoted by R(A1, A2, …, An) is made up of the relation name R and the list of attributes Ai that it contains. A relation is defined as a set of tuples. Let r be the relation which contains set tuples (t1, t2, t3, ..., tn). Each tuple is an ordered list of n-values t=(v1,v2, ..., vn).

What is degree of a Relation?
It is the number of attribute of its relation schema.

What is Relationship?
It is an association among two or more entities.

What is Relationship set?
The collection (or set) of similar relationships.

What is Relationship type?
Relationship type defines a set of associations or a relationship set among a given set of entity types.

What is degree of Relationship type?
It is the number of entity type participating.

What is DDL (Data Definition Language)?
A data base schema is specifies by a set of definitions expressed by a special language called DDL.

What is VDL (View Definition Language)?
It specifies user views and their mappings to the conceptual schema.

What is SDL (Storage Definition Language)?
This language is to specify the internal schema. This language may specify the mapping between two schemas.

What is Data Storage - Definition Language?
The storage structures and access methods used by database system are specified by a set of definition in a special type of DDL called data storage-definition language.

What is DML (Data Manipulation Language)?
This language that enable user to access or manipulate data as organised by appropriate data model.
Procedural DML or Low level: DML requires a user to specify what data are needed and how to get those data.
Non-Procedural DML or High level: DML requires a user to specify what data are needed without specifying how to get those data.

What is DML Compiler?
It translates DML statements in a query language into low-level instruction that the query evaluation engine can understand.

What is Query evaluation engine?
It executes low-level instruction generated by compiler.

What is DDL Interpreter?
It interprets DDL statements and record them in tables containing metadata.

What is Record-at-a-time?
The Low level or Procedural DML can specify and retrieve each record from a set of records. This retrieve of a record is said to be Record-at-a-time.

What is Set-at-a-time or Set-oriented?
The High level or Non-procedural DML can specify and retrieve many records in a single DML statement. This retrieve of a record is said to be Set-at-a-time or Set-oriented.

What is Relational Algebra?
It is procedural query language. It consists of a set of operations that take one or two relations as input and produce a new relation.

What is Relational Calculus?
It is an applied predicate calculus specifically tailored for relational databases proposed by E.F. Codd. E.g. of languages based on it are DSL ALPHA, QUEL.

How does Tuple-oriented relational calculus differ from domain-oriented relational calculus
The tuple-oriented calculus uses a tuple variables i.e., variable whose only permitted values are tuples of that relation. E.g. QUEL
The domain-oriented calculus has domain variables i.e., variables that range over the underlying domains instead of over relation. E.g. ILL, DEDUCE.

What is normalization?
It is a process of analysing the given relation schemas based on their Functional Dependencies (FDs) and primary key to achieve the properties
Minimizing redundancy
Minimizing insertion, deletion and update anomalies.

What is Functional Dependency?
A Functional dependency is denoted by X Y between two sets of attributes X and Y that are subsets of R specifies a constraint on the possible tuple that can form a relation state r of R. The constraint is for any two tuples t1 and t2 in r if t1[X] = t2[X] then they have t1[Y] = t2[Y]. This means the value of X component of a tuple uniquely determines the value of component Y.

When is a functional dependency F said to be minimal?
Every dependency in F has a single attribute for its right hand side.
We cannot replace any dependency X A in F with a dependency Y A where Y is a proper subset of X and still have a set of dependency that is equivalent to F.
We cannot remove any dependency from F and still have set of dependency that is equivalent to F.

What is Multivalued dependency?
Multivalued dependency denoted by X Y specified on relation schema R, where X and Y are both subsets of R, specifies the following constraint on any relation r of R: if two tuples t1 and t2 exist in r such that t1[X] = t2[X] then t3 and t4 should also exist in r with the following properties
t3[x] = t4[X] = t1[X] = t2[X]
t3[Y] = t1[Y] and t4[Y] = t2[Y]
t3[Z] = t2[Z] and t4[Z] = t1[Z]
where [Z = (R-(X U Y)) ]

What is Lossless join property?
It guarantees that the spurious tuple generation does not occur with respect to relation schemas after decomposition.

What is 1 NF (Normal Form)?
The domain of attribute must include only atomic (simple, indivisible) values.

What is Fully Functional dependency?
It is based on concept of full functional dependency. A functional dependency X Y is full functional dependency if removal of any attribute A from X means that the dependency does not hold any more.

What is 2NF?
A relation schema R is in 2NF if it is in 1NF and every non-prime attribute A in R is fully functionally dependent on primary key.

What is 3NF?
A relation schema R is in 3NF if it is in 2NF and for every FD X A either of the following is true
X is a Super-key of R.
A is a prime attribute of R.
In other words, if every non prime attribute is non-transitively dependent on primary key.

What is BCNF (Boyce-Codd Normal Form)?
A relation schema R is in BCNF if it is in 3NF and satisfies an additional constraint that for every FD X A, X must be a candidate key.

What is 4NF?
A relation schema R is said to be in 4NF if for every Multivalued dependency X Y that holds over R, one of following is true
X is subset or equal to (or) XY = R.
X is a super key.

What is 5NF?
A Relation schema R is said to be 5NF if for every join dependency {R1, R2, ..., Rn} that holds R, one the following is true
Ri = R for some i.
The join dependency is implied by the set of FD, over R in which the left side is key of R.
What is Domain-Key Normal Form?
A relation is said to be in DKNF if all constraints and dependencies that should hold on the the constraint can be enforced by simply enforcing the domain constraint and key constraint on the relation.

What are partial, alternate,, artificial, compound and natural key?
Partial Key:
It is a set of attributes that can uniquely identify weak entities and that are related to same owner entity. It is sometime called as Discriminator.
Alternate Key:
All Candidate Keys excluding the Primary Key are known as Alternate Keys.
Artificial Key:
If no obvious key, either stand alone or compound is available, then the last resort is to simply create a key, by assigning a unique number to each record or occurrence. Then this is known as developing an artificial key.
Compound Key:
If no single data element uniquely identifies occurrences within a construct, then combining multiple elements to create a unique identifier for the construct is known as creating a compound key.
Natural Key:
When one of the data elements stored within a construct is utilized as the primary key, then it is called the natural key.

What is indexing and what are the different kinds of indexing?
Indexing is a technique for determining how quickly specific data can be found.
Types:
Binary search style indexing
B-Tree indexing
Inverted list indexing
Memory resident table
Table indexing

What is system catalog or catalog relation? How is better known as?
A RDBMS maintains a description of all the data that it contains, information about every relation and index that it contains. This information is stored in a collection of relations maintained by the system called metadata. It is also called data dictionary.

What is meant by query optimization?
The phase that identifies an efficient execution plan for evaluating a query that has the least estimated cost is referred to as query optimization.

What is join dependency and inclusion dependency?
Join Dependency:
A Join dependency is generalization of Multivalued dependency.A JD {R1, R2, ..., Rn} is said to hold over a relation R if R1, R2, R3, ..., Rn is a lossless-join decomposition of R . There is no set of sound and complete inference rules for JD.
Inclusion Dependency:
An Inclusion Dependency is a statement of the form that some columns of a relation are contained in other columns. A foreign key constraint is an example of inclusion dependency.

What is durability in DBMS?
Once the DBMS informs the user that a transaction has successfully completed, its effects should persist even if the system crashes before all its changes are reflected on disk. This property is called durability.

What do you mean by atomicity and aggregation?
Atomicity:
Either all actions are carried out or none are. Users should not have to worry about the effect of incomplete transactions. DBMS ensures this by undoing the actions of incomplete transactions.
Aggregation:
A concept which is used to model a relationship between a collection of entities and relationships. It is used when we need to express a relationship among relationships.

What is a Phantom Deadlock?
In distributed deadlock detection, the delay in propagating local information might cause the deadlock detection algorithms to identify deadlocks that do not really exist. Such situations are called phantom deadlocks and they lead to unnecessary aborts.

What is a checkpoint and When does it occur?
A Checkpoint is like a snapshot of the DBMS state. By taking checkpoints, the DBMS can reduce the amount of work to be done during restart in the event of subsequent crashes.

What are the different phases of transaction?
Different phases are
Analysis phase
Redo Phase
Undo phase

What do you mean by flat file database?
It is a database in which there are no programs or user access languages. It has no cross-file capabilities but is user-friendly and provides user-interface management.

What is "transparent DBMS"?
It is one, which keeps its Physical Structure hidden from user.

Brief theory of Network, Hierarchical schemas and their properties
Network schema uses a graph data structure to organize records example for such a database management system is CTCG while a hierarchical schema uses a tree data structure example for such a system is IMS.

What is a query?
A query with respect to DBMS relates to user commands that are used to interact with a data base. The query language can be classified into data definition language and data manipulation language.

What do you mean by Correlated subquery?
Subqueries, or nested queries, are used to bring back a set of rows to be used by the parent query. Depending on how the subquery is written, it can be executed once for the parent query or it can be executed once for each row returned by the parent query. If the subquery is executed for each row of the parent, this is called a correlated subquery.
A correlated subquery can be easily identified if it contains any references to the parent subquery columns in its WHERE clause. Columns from the subquery cannot be referenced anywhere else in the parent query. The following example demonstrates a non-correlated subquery.
E.g. Select * From CUST Where '10/03/1990' IN (Select ODATE From ORDER Where CUST.CNUM = ORDER.CNUM)

What are the primitive operations common to all record management systems?
Addition, deletion and modification.

Name the buffer in which all the commands that are typed in are stored
‘Edit’ Buffer

What are the unary operations in Relational Algebra?
PROJECTION and SELECTION.

Are the resulting relations of PRODUCT and JOIN operation the same?
No.
PRODUCT: Concatenation of every row in one relation with every row in another.
JOIN: Concatenation of rows from one relation and related rows from another.

What is RDBMS KERNEL?
Two important pieces of RDBMS architecture are the kernel, which is the software, and the data dictionary, which consists of the system-level data structures used by the kernel to manage the database
You might think of an RDBMS as an operating system (or set of subsystems), designed specifically for controlling data access; its primary functions are storing, retrieving, and securing data. An RDBMS maintains its own list of authorized users and their associated privileges; manages memory caches and paging; controls locking for concurrent resource usage; dispatches and schedules user requests; and manages space usage within its table-space structures
.
Name the sub-systems of a RDBMS
I/O, Security, Language Processing, Process Control, Storage Management, Logging and Recovery, Distribution Control, Transaction Control, Memory Management, Lock Management

Which part of the RDBMS takes care of the data dictionary? How
Data dictionary is a set of tables and database objects that is stored in a special area of the database and maintained exclusively by the kernel.

What is the job of the information stored in data-dictionary?
The information in the data dictionary validates the existence of the objects, provides access to them, and maps the actual physical storage location.

Not only RDBMS takes care of locating data it also
determines an optimal access path to store or retrieve the data

How do you communicate with an RDBMS?
You communicate with an RDBMS using Structured Query Language (SQL)

Define SQL and state the differences between SQL and other conventional programming Languages
SQL is a nonprocedural language that is designed specifically for data access operations on normalized relational database structures. The primary difference between SQL and other conventional programming languages is that SQL statements specify what data operations should be performed rather than how to perform them.

Name the three major set of files on disk that compose a database in Oracle
There are three major sets of files on disk that compose a database. All the files are binary. These are
Database files
Control files
Redo logs
The most important of these are the database files where the actual data resides. The control files and the redo logs support the functioning of the architecture itself.
All three sets of files must be present, open, and available to Oracle for any data on the database to be useable. Without these files, you cannot access the database, and the database administrator might have to recover some or all of the database using a backup, if there is one.

What is an Oracle Instance?
The Oracle system processes, also known as Oracle background processes, provide functions for the user processes—functions that would otherwise be done by the user processes themselves
Oracle database-wide system memory is known as the SGA, the system global area or shared global area. The data and control structures in the SGA are shareable, and all the Oracle background processes and user processes can use them.
The combination of the SGA and the Oracle background processes is known as an Oracle instance

What are the four Oracle system processes that must always be up and running for the database to be useable
The four Oracle system processes that must always be up and running for the database to be useable include DBWR (Database Writer), LGWR (Log Writer), SMON (System Monitor), and PMON (Process Monitor).

What are database files, control files and log files. How many of these files should a database have at least? Why?
Database Files
The database files hold the actual data and are typically the largest in size. Depending on their sizes, the tables (and other objects) for all the user accounts can go in one database file—but that's not an ideal situation because it does not make the database structure very flexible for controlling access to storage for different users, putting the database on different disk drives, or backing up and restoring just part of the database.
You must have at least one database file but usually, more than one files are used. In terms of accessing and using the data in the tables and other objects, the number (or location) of the files is immaterial.
The database files are fixed in size and never grow bigger than the size at which they were created
Control Files
The control files and redo logs support the rest of the architecture. Any database must have at least one control file, although you typically have more than one to guard against loss. The control file records the name of the database, the date and time it was created, the location of the database and redo logs, and the synchronization information to ensure that all three sets of files are always in step. Every time you add a new database or redo log file to the database, the information is recorded in the control files.
Redo Logs
Any database must have at least two redo logs. These are the journals for the database; the redo logs record all changes to the user objects or system objects. If any type of failure occurs, the changes recorded in the redo logs can be used to bring the database to a consistent state without losing any committed transactions. In the case of non-data loss failure, Oracle can apply the information in the redo logs automatically without intervention from the DBA.
The redo log files are fixed in size and never grow dynamically from the size at which they were created.

What is ROWID?
The ROWID is a unique database-wide physical address for every row on every table. Once assigned (when the row is first inserted into the database), it never changes until the row is deleted or the table is dropped.
The ROWID consists of the following three components, the combination of which uniquely identifies the physical storage location of the row.
Oracle database file number, which contains the block with the rows
Oracle block address, which contains the row
The row within the block (because each block can hold many rows)
The ROWID is used internally in indexes as a quick means of retrieving rows with a particular key value. Application developers also use it in SQL statements as a quick way to access a row once they know the ROWID

What is Oracle Block? Can two Oracle Blocks have the same address?
Oracle "formats" the database files into a number of Oracle blocks when they are first created—making it easier for the RDBMS software to manage the files and easier to read data into the memory areas.
The block size should be a multiple of the operating system block size. Regardless of the block size, the entire block is not available for holding data; Oracle takes up some space to manage the contents of the block. This block header has a minimum size, but it can grow.
These Oracle blocks are the smallest unit of storage. Increasing the Oracle block size can improve performance, but it should be done only when the database is first created.
Each Oracle block is numbered sequentially for each database file starting at 1. Two blocks can have the same block address if they are in different database files.

What is database Trigger?
A database trigger is a PL/SQL block that can defined to automatically execute for insert, update, and delete statements against a table. The trigger can e defined to execute once for the entire statement or once for every row that is inserted, updated, or deleted. For any one table, there are twelve events for which you can define database triggers. A database trigger can call database procedures that are also written in PL/SQL.

Name two utilities that Oracle provides, which are use for backup and recovery.
Along with the RDBMS software, Oracle provides two utilities that you can use to back up and restore the database. These utilities are Export and Import.
The Export utility dumps the definitions and data for the specified part of the database to an operating system binary file. The Import utility reads the file produced by an export, recreates the definitions of objects, and inserts the data
If Export and Import are used as a means of backing up and recovering the database, all the changes made to the database cannot be recovered since the export was performed. The best you can do is recover the database to the time when the export was last performed.

What are stored-procedures? And what are the advantages of using them.
Stored procedures are database objects that perform a user defined operation. A stored procedure can have a set of compound SQL statements. A stored procedure executes the SQL commands and returns the result to the client. Stored procedures are used to reduce network traffic.

How are exceptions handled in PL/SQL? Give some of the internal exceptions' name
PL/SQL exception handling is a mechanism for dealing with run-time errors encountered during procedure execution. Use of this mechanism enables execution to continue if the error is not severe enough to cause procedure termination.
The exception handler must be defined within a subprogram specification. Errors cause the program to raise an exception with a transfer of control to the exception-handler block. After the exception handler executes, control returns to the block in which the handler was defined. If there are no more executable statements in the block, control returns to the caller.
User-Defined Exceptions
PL/SQL enables the user to define exception handlers in the declarations area of subprogram specifications. User accomplishes this by naming an exception as in the following example:
ot_failure EXCEPTION;
In this case, the exception name is ot_failure. Code associated with this handler is written in the EXCEPTION specification area as follows:
EXCEPTION
when OT_FAILURE then
out_status_code := g_out_status_code;
out_msg := g_out_msg;
The following is an example of a subprogram exception:
EXCEPTION
when NO_DATA_FOUND then
g_out_status_code := 'FAIL';
RAISE ot_failure;
Within this exception is the RAISE statement that transfers control back to the ot_failure exception handler. This technique of raising the exception is used to invoke all user-defined exceptions.
System-Defined Exceptions
Exceptions internal to PL/SQL are raised automatically upon error. NO_DATA_FOUND is a system-defined exception. Table below gives a complete list of internal exceptions.

PL/SQL internal exceptions.

Exception Name Oracle Error
CURSOR_ALREADY_OPEN ORA-06511
DUP_VAL_ON_INDEX ORA-00001
INVALID_CURSOR ORA-01001
INVALID_NUMBER ORA-01722
LOGIN_DENIED ORA-01017
NO_DATA_FOUND ORA-01403
NOT_LOGGED_ON ORA-01012
PROGRAM_ERROR ORA-06501
STORAGE_ERROR ORA-06500
TIMEOUT_ON_RESOURCE ORA-00051
TOO_MANY_ROWS ORA-01422
TRANSACTION_BACKED_OUT ORA-00061
VALUE_ERROR ORA-06502
ZERO_DIVIDE ORA-01476

In addition to this list of exceptions, there is a catch-all exception named OTHERS that traps all errors for which specific error handling has not been established.

Does PL/SQL support "overloading"? Explain
The concept of overloading in PL/SQL relates to the idea that you can define procedures and functions with the same name. PL/SQL does not look only at the referenced name, however, to resolve a procedure or function call. The count and data types of formal parameters are also considered.
PL/SQL also attempts to resolve any procedure or function calls in locally defined packages before looking at globally defined packages or internal functions. To further ensure calling the proper procedure, you can use the dot notation. Prefacing a procedure or function name with the package name fully qualifies any procedure or function reference.

Tables derived from the ERD
a) Are totally unnormalised
b) Are always in 1NF
c) Can be further denormalised
d) May have multi-valued attributes

(b) Are always in 1NF

Spurious tuples may occur due to
i. Bad normalization
ii. Theta joins
iii. Updating tables from join
a) i & ii b) ii & iii
c) i & iii d) ii & iii

(a) i & iii because theta joins are joins made on keys that are not primary keys.

A B C is a set of attributes. The functional dependency is as follows
AB -> B
AC -> C
C -> B
a) is in 1NF
b) is in 2NF
c) is in 3NF
d) is in BCNF

(a) is in 1NF since (AC)+ = { A, B, C} hence AC is the primary key. Since C B is a FD given, where neither C is a Key nor B is a prime attribute, this it is not in 3NF. Further B is not functionally dependent on key AC thus it is not in 2NF. Thus the given FDs is in 1NF.

In mapping of ERD to DFD
a) entities in ERD should correspond to an existing entity/store in DFD
b) entity in DFD is converted to attributes of an entity in ERD
c) relations in ERD has 1 to 1 correspondence to processes in DFD
d) relationships in ERD has 1 to 1 correspondence to flows in DFD

(a) entities in ERD should correspond to an existing entity/store in DFD

A dominant entity is the entity
a) on the N side in a 1 : N relationship
b) on the 1 side in a 1 : N relationship
c) on either side in a 1 : 1 relationship
d) nothing to do with 1 : 1 or 1 : N relationship

(b) on the 1 side in a 1 : N relationship

Select 'NORTH', CUSTOMER From CUST_DTLS Where REGION = 'N' Order By
CUSTOMER Union Select 'EAST', CUSTOMER From CUST_DTLS Where REGION = 'E' Order By CUSTOMER
The above is
a) Not an error
b) Error - the string in single quotes 'NORTH' and 'SOUTH'
c) Error - the string should be in double quotes
d) Error - ORDER BY clause

(d) Error - the ORDER BY clause. Since ORDER BY clause cannot be used in UNIONS

What is Storage Manager?
It is a program module that provides the interface between the low-level data stored in database, application programs and queries submitted to the system.

What is Buffer Manager?
It is a program module, which is responsible for fetching data from disk storage into main memory and deciding what data to be cache in memory.

What is Transaction Manager?
It is a program module, which ensures that database, remains in a consistent state despite system failures and concurrent transaction execution proceeds without conflicting.

What is File Manager?
It is a program module, which manages the allocation of space on disk storage and data structure used to represent information stored on a disk.

What is Authorization and Integrity manager?
It is the program module, which tests for the satisfaction of integrity constraint and checks the authority of user to access data.

What are stand-alone procedures?
Procedures that are not part of a package are known as stand-alone because they independently defined. A good example of a stand-alone procedure is one written in a SQL*Forms application. These types of procedures are not available for reference from other Oracle tools. Another limitation of stand-alone procedures is that they are compiled at run time, which slows execution.

What are cursors give different types of cursors.
PL/SQL uses cursors for all database information accesses statements. The language supports the use two types of cursors
Implicit
Explicit

What is cold backup and hot backup (in case of Oracle)?
Cold Backup:
It is copying the three sets of files (database files, redo logs, and control file) when the instance is shut down. This is a straight file copy, usually from the disk directly to tape. You must shut down the instance to guarantee a consistent copy.
If a cold backup is performed, the only option available in the event of data file loss is restoring all the files from the latest backup. All work performed on the database since the last backup is lost.
Hot Backup:
Some sites (such as worldwide airline reservations systems) cannot shut down the database while making a backup copy of the files. The cold backup is not an available option.
So different means of backing up database must be used — the hot backup. Issue a SQL command to indicate to Oracle, on a tablespace-by-tablespace basis, that the files of the tablespace are to backed up. The users can continue to make full use of the files, including making changes to the data. Once the user has indicated that he/she wants to back up the tablespace files, he/she can use the operating system to copy those files to the desired backup destination.
The database must be running in ARCHIVELOG mode for the hot backup option.
If a data loss failure does occur, the lost database files can be restored using the hot backup and the online and offline redo logs created since the backup was done. The database is restored to the most consistent state without any loss of committed transactions.

What are Armstrong rules? How do we say that they are complete and/or sound
The well-known inference rules for FDs
Reflexive rule :
If Y is subset or equal to X then X Y.
Augmentation rule:
If X Y then XZ YZ.
Transitive rule:
If {X Y, Y Z} then X Z.
Decomposition rule :
If X YZ then X Y.
Union or Additive rule:
If {X Y, X Z} then X YZ.
Pseudo Transitive rule :
If {X Y, WY Z} then WX Z.
Of these the first three are known as Amstrong Rules. They are sound because it is enough if a set of FDs satisfy these three. They are called complete because using these three rules we can generate the rest all inference rules.

How can you find the minimal key of relational schema?
Minimal key is one which can identify each tuple of the given relation schema uniquely. For finding the minimal key it is required to find the closure that is the set of all attributes that are dependent on any given set of attributes under the given set of functional dependency.
Algo. I Determining X+, closure for X, given set of FDs F
1. Set X+ = X
2. Set Old X+ = X+
3. For each FD Y Z in F and if Y belongs to X+ then add Z to X+
4. Repeat steps 2 and 3 until Old X+ = X+

Algo.II Determining minimal K for relation schema R, given set of FDs F
1. Set K to R that is make K a set of all attributes in R
2. For each attribute A in K
a. Compute (K – A)+ with respect to F
b. If (K – A)+ = R then set K = (K – A)+

What do you understand by dependency preservation?
Given a relation R and a set of FDs F, dependency preservation states that the closure of the union of the projection of F on each decomposed relation Ri is equal to the closure of F. i.e.,
((PR1(F)) U … U (PRn(F)))+ = F+
if decomposition is not dependency preserving, then some dependency is lost in the decomposition.

What is meant by Proactive, Retroactive and Simultaneous Update.
Proactive Update:
The updates that are applied to database before it becomes effective in real world .
Retroactive Update:
The updates that are applied to database after it becomes effective in real world .
Simulatneous Update:
The updates that are applied to database at the same time when it becomes effective in real world .

What are the different types of JOIN operations?
Equi Join: This is the most common type of join which involves only equality comparisions. The disadvantage in this type of join is that there

Data Structure Aptitude Questions

What is data structure?
A data structure is a way of organizing data that considers not only the items stored, but also their relationship to each other. Advance knowledge about the relationship between data items allows designing of efficient algorithms for the manipulation of data.

List out the areas in which data structures are applied extensively?
Compiler Design,
Operating System,
Database Management System,
Statistical analysis package,
Numerical Analysis,
Graphics,
Artificial Intelligence,
Simulation

What are the major data structures used in the following areas : RDBMS, Network data model & Hierarchical data model.
RDBMS – Array (i.e. Array of structures)
Network data model – Graph
Hierarchical data model – Trees

If you are using C language to implement the heterogeneous linked list, what pointer type will you use?
The heterogeneous linked list contains different data types in its nodes and we need a link, pointer to connect them. It is not possible to use ordinary pointers for this. So we go for void pointer. Void pointer is capable of storing pointer to any type as it is a generic pointer type.

Minimum number of queues needed to implement the priority queue?
Two. One queue is used for actual storing of data and another for storing priorities.

What is the data structures used to perform recursion?
Stack. Because of its LIFO (Last In First Out) property it remembers its ‘caller’ so knows whom to return when the function has to return. Recursion makes use of system stack for storing the return addresses of the function calls.
Every recursive function has its equivalent iterative (non-recursive) function. Even when such equivalent iterative procedures are written, explicit stack is to be used.

What are the notations used in Evaluation of Arithmetic Expressions using prefix and postfix forms?
Polish and Reverse Polish notations.

Convert the expression ((A + B) * C – (D – E) ^ (F + G)) to equivalent Prefix and Postfix notations.
Prefix Notation:
^ - * +ABC - DE + FG
Postfix Notation:
AB + C * DE - - FG + ^

Sorting is not possible by using which of the following methods?
(a) Insertion
(b) Selection
(c) Exchange
(d) Deletion

(d) Deletion.
Using insertion we can perform insertion sort, using selection we can perform selection sort, using exchange we can perform the bubble sort (and other similar sorting methods). But no sorting method can be done just using deletion.

A binary tree with 20 nodes has null branches?
21
Let us take a tree with 5 nodes (n=5)

It will have only 6 (ie,5+1) null branches. In general,
A binary tree with n nodes has exactly n+1 null nodes.

What are the methods available in storing sequential files ?
Straight merging,
Natural merging,
Polyphase sort,
Distribution of Initial runs.

How many different trees are possible with 10 nodes ?
1014
For example, consider a tree with 3 nodes(n=3), it will have the maximum combination of 5 different (ie, 23 - 3 = 5) trees.

i ii iii iv v

In general:
If there are n nodes, there exist 2n-n different trees.

List out few of the Application of tree data-structure?
The manipulation of Arithmetic expression,
Symbol Table construction,
Syntax analysis.

List out few of the applications that make use of Multilinked Structures?
Sparse matrix,
Index generation.

In tree construction which is the suitable efficient data structure?
(a) Array (b) Linked list (c) Stack (d) Queue (e) none

(b) Linked list

What is the type of the algorithm used in solving the 8 Queens problem?
Backtracking

In an AVL tree, at what condition the balancing is to be done?
If the ‘pivotal value’ (or the ‘Height factor’) is greater than 1 or less than –1.

What is the bucket size, when the overlapping and collision occur at same time?
One. If there is only one entry possible in the bucket, when the collision occurs, there is no way to accommodate the colliding value. This results in the overlapping of values.

Traverse the given tree using Inorder, Preorder and Postorder traversals.

Inorder : D H B E A F C I G J
Preorder: A B D H E C F G I J
Postorder: H D E B F I J G C A

There are 8, 15, 13, 14 nodes were there in 4 different trees. Which of them could have formed a full binary tree?
15.
In general:
There are 2n-1 nodes in a full binary tree.
By the method of elimination:
Full binary trees contain odd number of nodes. So there cannot be full binary trees with 8 or 14 nodes, so rejected. With 13 nodes you can form a complete binary tree but not a full binary tree. So the correct answer is 15.
Note:
Full and Complete binary trees are different. All full binary trees are complete binary trees but not vice versa.

In the given binary tree, using array you can store the node 4 at which location?

At location 6

1 2 3 - - 4 - - 5

Root LC1 RC1 LC2 RC2 LC3 RC3 LC4 RC4

where LCn means Left Child of node n and RCn means Right Child of node n

Sort the given values using Quick Sort?

65 70 75 80 85 60 55 50 45

Sorting takes place from the pivot value, which is the first value of the given elements, this is marked bold. The values at the left pointer and right pointer are indicated using L and R respectively.

65 70L 75 80 85 60 55 50 45R

Since pivot is not yet changed the same process is continued after interchanging the values at L and R positions

65 45 75 L 80 85 60 55 50 R 70

65 45 50 80 L 85 60 55 R 75 70

65 45 50 55 85 L 60 R 80 75 70

65 45 50 55 60 R 85 L 80 75 70

When the L and R pointers cross each other the pivot value is interchanged with the value at right pointer. If the pivot is changed it means that the pivot has occupied its original position in the sorted order (shown in bold italics) and hence two different arrays are formed, one from start of the original array to the pivot position-1 and the other from pivot position+1 to end.

60 L 45 50 55 R 65 85 L 80 75 70 R

55 L 45 50 R 60 65 70 R 80 L 75 85

50 L 45 R 55 60 65 70 80 L 75 R 85

In the next pass we get the sorted form of the array.

45 50 55 60 65 70 75 80 85

For the given graph, draw the DFS and BFS?

BFS: A X G H P E M Y J

DFS: A X H P E Y M J G

Classify the Hashing Functions based on the various methods by which the key value is found.
Direct method,
Subtraction method,
Modulo-Division method,
Digit-Extraction method,
Mid-Square method,
Folding method,
Pseudo-random method.

What are the types of Collision Resolution Techniques and the methods used in each of the type?
Open addressing (closed hashing),
The methods used include:
Overflow block,
Closed addressing (open hashing)
The methods used include:
Linked list,
Binary tree…

In RDBMS, what is the efficient data structure used in the internal storage representation?
B+ tree. Because in B+ tree, all the data is stored only in leaf nodes, that makes searching easier. This corresponds to the records that shall be stored in leaf nodes.

Draw the B-tree of order 3 created by inserting the following data arriving in sequence – 92 24 6 7 11 8 22 4 5 16 19 20 78

Of the following tree structure, which is, efficient considering space and time complexities?
Incomplete Binary Tree
Complete Binary Tree
Full Binary Tree

(b) Complete Binary Tree.
By the method of elimination:
Full binary tree loses its nature when operations of insertions and deletions are done. For incomplete binary trees, extra storage is required and overhead of NULL node checking takes place. So complete binary tree is the better one since the property of complete binary tree is maintained even after operations like additions and deletions are done on it.

What is a spanning Tree?
A spanning tree is a tree associated with a network. All the nodes of the graph appear on the tree once. A minimum spanning tree is a spanning tree organized so that the total edge weight between nodes is minimized.

Does the minimum spanning tree of a graph give the shortest distance between any 2 specified nodes?
No.
Minimal spanning tree assures that the total weight of the tree is kept at its minimum. But it doesn’t mean that the distance between any two nodes involved in the minimum-spanning tree is minimum.

Convert the given graph with weighted edges to minimal spanning tree.

the equivalent minimal spanning tree is:

Which is the simplest file structure?
Sequential
Indexed
Random
(a) Sequential

Whether Linked List is linear or Non-linear data structure?
According to Access strategies Linked list is a linear one.
According to Storage Linked List is a Non-linear one.

Draw a binary Tree for the expression :
A * B - (C + D) * (P / Q)

Networking Aptitude concepts

1. What are the two types of transmission technology available?

(i) Broadcast and (ii) point-to-point

2. What is subnet?

A generic term for section of a large networks usually separated by a bridge or router.

3. Difference between the communication and transmission.

Transmission is a physical movement of information and concern issues like bit polarity, synchronisation, clock etc.

Communication means the meaning full exchange of information between two communication media.

4. What are the possible ways of data exchange?

(i) Simplex (ii) Half-duplex (iii) Full-duplex.

5. What is SAP?

Series of interface points that allow other computers to communicate with the other layers of network protocol stack.

6. What do you meant by "triple X" in Networks?

The function of PAD (Packet Assembler Disassembler) is described in a document known as X.3. The standard protocol has been defined between the terminal and the PAD, called X.28; another standard protocol exists between hte PAD and the network, called X.29. Together, these three recommendations are often called "triple X"

7. What is frame relay, in which layer it comes?

Frame relay is a packet switching technology. It will operate in the data link layer.

8. What is terminal emulation, in which layer it comes?

Telnet is also called as terminal emulation. It belongs to application layer.

9. What is Beaconing?

The process that allows a network to self-repair networks problems. The stations on the network notify the other stations on the ring when they are not receiving the transmissions. Beaconing is used in Token ring and FDDI networks.

10. What is redirector?

Redirector is software that intercepts file or prints I/O requests and translates them into network requests. This comes under presentation layer.

11. What is NETBIOS and NETBEUI?

NETBIOS is a programming interface that allows I/O requests to be sent to and received from a remote computer and it hides the networking hardware from applications.

NETBEUI is NetBIOS extended user interface. A transport protocol designed by microsoft and IBM for the use on small subnets.

12. What is RAID?

A method for providing fault tolerance by using multiple hard disk drives.

13. What is passive topology?

When the computers on the network simply listen and receive the signal, they are referred to as passive because they don’t amplify the signal in any way. Example for passive topology - linear bus.

14. What is Brouter?

Hybrid devices that combine the features of both bridges and routers.

15. What is cladding?

A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.

16. What is point-to-point protocol

A communications protocol used to connect computers to remote networking services including Internet service providers.

17. How Gateway is different from Routers?

A gateway operates at the upper levels of the OSI model and translates information between two completely different network architectures or data formats

18. What is attenuation?

The degeneration of a signal over distance on a network cable is called attenuation.

19. What is MAC address?

The address for a device as it is identified at the Media Access Control (MAC) layer in the network architecture. MAC address is usually stored in ROM on the network adapter card and is unique.

20. Difference between bit rate and baud rate.

Bit rate is the number of bits transmitted during one second whereas baud rate refers to the number of signal units per second that are required to represent those bits.

baud rate = bit rate / N

where N is no-of-bits represented by each signal shift.

21. What is Bandwidth?

Every line has an upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the bandwidth.

22. What are the types of Transmission media?

Signals are usually transmitted over some transmission media that are broadly classified in to two categories.

a) Guided Media:

These are those that provide a conduit from one device to another that include twisted-pair, coaxial cable and fiber-optic cable. A signal traveling along any of these media is directed and is contained by the physical limits of the medium. Twisted-pair and coaxial cable use metallic that accept and transport signals in the form of electrical current. Optical fiber is a glass or plastic cable that accepts and transports signals in the form of light.

b) Unguided Media:

This is the wireless media that transport electromagnetic waves without using a physical conductor. Signals are broadcast either through air. This is done through radio communication, satellite communication and cellular telephony.

23. What is Project 802?

It is a project started by IEEE to set standards to enable intercommunication between equipment from a variety of manufacturers. It is a way for specifying functions of the physical layer, the data link layer and to some extent the network layer to allow for interconnectivity of major LAN

protocols.

It consists of the following:

Ø 802.1 is an internetworking standard for compatibility of different LANs and MANs across protocols.

Ø 802.2 Logical link control (LLC) is the upper sublayer of the data link layer which is non-architecture-specific, that is remains the same for all IEEE-defined LANs.

Ø Media access control (MAC) is the lower sublayer of the data link layer that contains some distinct modules each carrying proprietary information specific to the LAN product being used. The modules are Ethernet LAN (802.3), Token ring LAN (802.4), Token bus LAN (802.5).

Ø 802.6 is distributed queue dual bus (DQDB) designed to be used in MANs.

24. What is Protocol Data Unit?

The data unit in the LLC level is called the protocol data unit (PDU). The PDU contains of four fields a destination service access point (DSAP), a source service access point (SSAP), a control field and an information field. DSAP, SSAP are addresses used by the LLC to identify the protocol stacks on the receiving and sending machines that are generating and using the data. The control field specifies whether the PDU frame is a information frame (I - frame) or a supervisory frame (S - frame) or a unnumbered frame (U - frame).

25. What are the different type of networking / internetworking devices?

Repeater:

Also called a regenerator, it is an electronic device that operates only at physical layer. It receives the signal in the network before it becomes weak, regenerates the original bit pattern and puts the refreshed copy back in to the link.

Bridges:

These operate both in the physical and data link layers of LANs of same type. They divide a larger network in to smaller segments. They contain logic that allow them to keep the traffic for each segment separate and thus are repeaters that relay a frame only the side of the segment containing the intended recipent and control congestion.

Routers:

They relay packets among multiple interconnected networks (i.e. LANs of different type). They operate in the physical, data link and network layers. They contain software that enable them to determine which of the several possible paths is the best for a particular transmission.

Gateways:

They relay packets among networks that have different protocols (e.g. between a LAN and a WAN). They accept a packet formatted for one protocol and convert it to a packet formatted for another protocol before forwarding it. They operate in all seven layers of the OSI model.

26. What is ICMP?

ICMP is Internet Control Message Protocol, a network layer protocol of the TCP/IP suite used by hosts and gateways to send notification of datagram problems back to the sender. It uses the echo test / reply to test whether a destination is reachable and responding. It also handles both control and error messages.

27. What are the data units at different layers of the TCP / IP protocol suite?

The data unit created at the application layer is called a message, at the transport layer the data unit created is called either a segment or an user datagram, at the network layer the data unit created is called the datagram, at the data link layer the datagram is encapsulated in to a frame and finally transmitted as signals along the transmission media.

28. What is difference between ARP and RARP?

The address resolution protocol (ARP) is used to associate the 32 bit IP address with the 48 bit physical address, used by a host or a router to find the physical address of another host on its network by sending a ARP query packet that includes the IP address of the receiver.

The reverse address resolution protocol (RARP) allows a host to discover its Internet address when it knows only its physical address.

29. What is the minimum and maximum length of the header in the TCP segment and IP datagram?

The header should have a minimum length of 20 bytes and can have a maximum length of 60 bytes.

30. What is the range of addresses in the classes of internet addresses?

Class A 0.0.0.0 - 127.255.255.255

Class B 128.0.0.0 - 191.255.255.255

Class C 192.0.0.0 - 223.255.255.255

Class D 224.0.0.0 - 239.255.255.255

Class E 240.0.0.0 - 247.255.255.255

31. What is the difference between TFTP and FTP application layer protocols?

The Trivial File Transfer Protocol (TFTP) allows a local host to obtain files from a remote host but does not provide reliability or security. It uses the fundamental packet delivery services offered by UDP.

The File Transfer Protocol (FTP) is the standard mechanism provided by TCP / IP for copying a file from one host to another. It uses the services offer by TCP and so is reliable and secure. It establishes two connections (virtual circuits) between the hosts, one for data transfer and another for control information.

32. What are major types of networks and explain?

Ø Server-based network

Ø Peer-to-peer network

Peer-to-peer network, computers can act as both servers sharing resources and as clients using the resources.

Server-based networks provide centralized control of network resources and rely on server computers to provide security and network administration

33. What are the important topologies for networks?

Ø BUS topology:

In this each computer is directly connected to primary network cable in a single line.

Advantages:

Inexpensive, easy to install, simple to understand, easy to extend.

Ø STAR topology:

In this all computers are connected using a central hub.

Advantages:

Can be inexpensive, easy to install and reconfigure and easy to trouble shoot physical problems.

Ø RING topology:

In this all computers are connected in loop.

Advantages:

All computers have equal access to network media, installation can be simple, and signal does not degrade as much as in other topologies because each computer regenerates it.

34. What is mesh network?

A network in which there are multiple network links between computers to provide multiple paths for data to travel.

35. What is difference between baseband and broadband transmission?

In a baseband transmission, the entire bandwidth of the cable is consumed by a single signal. In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.

36. Explain 5-4-3 rule?

In a Ethernet network, between any two points on the network ,there can be no more than five network segments or four repeaters, and of those five segments only three of segments can be populated.

37. What MAU?

In token Ring , hub is called Multistation Access Unit(MAU).

38. What is the difference between routable and non- routable protocols?

Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router

39. Why should you care about the OSI Reference Model?

It provides a framework for discussing network operations and design.

40. What is logical link control?

One of two sublayers of the data link layer of OSI reference model, as defined by the IEEE 802 standard. This sublayer is responsible for maintaining the link between computers when they are sending data across the physical network connection.

41. What is virtual channel?

Virtual channel is normally a connection from one source to one destination, although multicast connections are also permitted. The other name for virtual channel is virtual circuit.

42. What is virtual path?

Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path.

43. What is packet filter?

Packet filter is a standard router equipped with some extra functionality. The extra functionality allows every incoming or outgoing packet to be inspected. Packets meeting some criterion are forwarded normally. Those that fail the test are dropped.

44. What is traffic shaping?

One of the main causes of congestion is that traffic is often busy. If hosts could be made to transmit at a uniform rate, congestion would be less common. Another open loop method to help manage congestion is forcing the packet to be transmitted at a more predictable rate. This is called traffic shaping.

45. What is multicast routing?

Sending a message to a group is called multicasting, and its routing algorithm is called multicast routing.

46. What is region?

When hierarchical routing is used, the routers are divided into what we will call regions, with each router knowing all the details about how to route packets to destinations within its own region, but knowing nothing about the internal structure of other regions.

47. What is silly window syndrome?

It is a problem that can ruin TCP performance. This problem occurs when data are passed to the sending TCP entity in large blocks, but an interactive application on the receiving side reads 1 byte at a time.

48. What are Digrams and Trigrams?

The most common two letter combinations are called as digrams. e.g. th, in, er, re and an. The most common three letter combinations are called as trigrams. e.g. the, ing, and, and ion.

49. Expand IDEA.

IDEA stands for International Data Encryption Algorithm.

50. What is wide-mouth frog?

Wide-mouth frog is the simplest known key distribution center (KDC) authentication protocol.

51. What is Mail Gateway?

It is a system that performs a protocol translation between different electronic mail delivery protocols.

52. What is IGP (Interior Gateway Protocol)?

It is any routing protocol used within an autonomous system.

53. What is EGP (Exterior Gateway Protocol)?

It is the protocol the routers in neighboring autonomous systems use to identify the set of networks that can be reached within or via each autonomous system.

54. What is autonomous system?

It is a collection of routers under the control of a single administrative authority and that uses a common Interior Gateway Protocol.

55. What is BGP (Border Gateway Protocol)?

It is a protocol used to advertise the set of networks that can be reached with in an autonomous system. BGP enables this information to be shared with the autonomous system. This is newer than EGP (Exterior Gateway Protocol).

56. What is Gateway-to-Gateway protocol?

It is a protocol formerly used to exchange routing information between Internet core routers.

57. What is NVT (Network Virtual Terminal)?

It is a set of rules defining a very simple virtual terminal interaction. The NVT is used in the start of a Telnet session.

58. What is a Multi-homed Host?

It is a host that has a multiple network interfaces and that requires multiple IP addresses is called as a Multi-homed Host.

59. What is Kerberos?

It is an authentication service developed at the Massachusetts Institute of Technology. Kerberos uses encryption to prevent intruders from discovering passwords and gaining unauthorized access to files.

60. What is OSPF?

It is an Internet routing protocol that scales well, can route traffic along multiple paths, and uses knowledge of an Internet's topology to make accurate routing decisions.

61. What is Proxy ARP?

It is using a router to answer ARP requests. This will be done when the originating host believes that a destination is local, when in fact is lies beyond router.

62. What is SLIP (Serial Line Interface Protocol)?

It is a very simple protocol used for transmission of IP datagrams across a serial line.

63. What is RIP (Routing Information Protocol)?

It is a simple protocol used to exchange information between the routers.

64. What is source route?

It is a sequence of IP addresses identifying the route a datagram must follow. A source route may optionally be included in an IP datagram header.

For the following COBOL code, draw the Binary tree?

01 STUDENT_REC.
02 NAME.
03 FIRST_NAME PIC X(10).
03 LAST_NAME PIC X(10).

02 YEAR_OF_STUDY.
03 FIRST_SEM PIC XX.
03 SECOND_SEM PIC XX.

JAVA APTITUDE Tutorial

1.The Java interpreter is used for the execution of the source code.

True

False

Ans: a.

2) On successful compilation a file with the class extension is created.

a) True

b) False

Ans: a.

3) The Java source code can be created in a Notepad editor.

a) True

b) False

Ans: a.

4) The Java Program is enclosed in a class definition.

a) True

b) False

Ans: a.

5) What declarations are required for every Java application?

Ans: A class and the main( ) method declarations.

6) What are the two parts in executing a Java program and their purposes?

Ans: Two parts in executing a Java program are:

Java Compiler and Java Interpreter.

The Java Compiler is used for compilation and the Java Interpreter is used for execution of the application.

7) What are the three OOPs principles and define them?

Ans : Encapsulation, Inheritance and Polymorphism are the three OOPs

Principles.

Encapsulation:

Is the Mechanism that binds together code and the data it manipulates, and keeps both safe from outside interference and misuse.

Inheritance:

Is the process by which one object acquires the properties of another object.

Polymorphism:

Is a feature that allows one interface to be used for a general class of actions.

8) What is a compilation unit?

Ans : Java source code file.

9) What output is displayed as the result of executing the following statement?

System.out.println("// Looks like a comment.");

// Looks like a comment

The statement results in a compilation error

Looks like a comment

No output is displayed

Ans : a.

10) In order for a source code file, containing the public class Test, to successfully compile, which of the following must be true?

It must have a package statement

It must be named Test.java

It must import java.lang

It must declare a public class named Test

Ans : b

11) What are identifiers and what is naming convention?

Ans : Identifiers are used for class names, method names and variable names. An identifier may be any descriptive sequence of upper case & lower case letters,numbers or underscore or dollar sign and must not begin with numbers.

12) What is the return type of program’s main( ) method?

Ans : void

13) What is the argument type of program’s main( ) method?

Ans : string array.

14) Which characters are as first characters of an identifier?

Ans : A – Z, a – z, _ ,$

15) What are different comments?

Ans : 1) // -- single line comment

2) /* --

*/ multiple line comment

3) /** --

*/ documentation

16) What is the difference between constructor method and method?

Ans : Constructor will be automatically invoked when an object is created. Whereas method has to be call explicitly.

17) What is the use of bin and lib in JDK?

Ans : Bin contains all tools such as javac, applet viewer, awt tool etc., whereas Lib

contains all packages and variables.

Data types,variables and Arrays

1) What is meant by variable?

Ans: Variables are locations in memory that can hold values. Before assigning any value to a variable, it must be declared.

2) What are the kinds of variables in Java? What are their uses?

Ans: Java has three kinds of variables namely, the instance variable, the local variable and the class variable.

Local variables are used inside blocks as counters or in methods as temporary variables and are used to store information needed by a single method.

Instance variables are used to define attributes or the state of a particular object and are used to store information needed by multiple methods in the objects.

Class variables are global to a class and to all the instances of the class and are useful for communicating between different objects of all the same class or keeping track of global states.

3) How are the variables declared?

Ans: Variables can be declared anywhere in the method definition and can be initialized during their declaration.They are commonly declared before usage at the beginning of the definition.

Variables with the same data type can be declared together. Local variables must be given a value before usage.

4) What are variable types?

Ans: Variable types can be any data type that java supports, which includes the eight primitive data types, the name of a class or interface and an array.

5) How do you assign values to variables?

Ans: Values are assigned to variables using the assignment operator =.

6) What is a literal? How many types of literals are there?

Ans: A literal represents a value of a certain type where the type describes how that value behaves.

There are different types of literals namely number literals, character literals,

boolean literals, string literals,etc.

7) What is an array?

Ans: An array is an object that stores a list of items.

8) How do you declare an array?

Ans: Array variable indicates the type of object that the array holds.

Ex: int arr[];

9) Java supports multidimensional arrays.

a)True

b)False

Ans: a.

10) An array of arrays can be created.

a)True

b)False

Ans: a.

11) What is a string?

Ans: A combination of characters is called as string.

12) Strings are instances of the class String.

a)True

b)False

Ans: a.

13) When a string literal is used in the program, Java automatically creates instances of the string class.

a)True

b)False

Ans: a.

14) Which operator is to create and concatenate string?

Ans: Addition operator(+).

15) Which of the following declare an array of string objects?

String[ ] s;

String [ ]s:

String[ s]:

String s[ ]:

Ans : a, b and d

16) What is the value of a[3] as the result of the following array declaration?

1

2

3

4

Ans : d

17) Which of the following are primitive types?

byte

String

integer

Float

Ans : a.

18) What is the range of the char type?

0 to 216

0 to 215

0 to 216-1

0 to 215-1

Ans. d

19) What are primitive data types?

Ans : byte, short, int, long

float, double

boolean

char

20) What are default values of different primitive types?

Ans : int - 0

short - 0

byte - 0

long - 0 l

float - 0.0 f

double - 0.0 d

boolean - false

char - null

21) Converting of primitive types to objects can be explicitly.

a)True

b)False

Ans: b.

22) How do we change the values of the elements of the array?

Ans : The array subscript expression can be used to change the values of the elements of the array.

23) What is final varaible?

Ans : If a variable is declared as final variable, then you can not change its value. It becomes constant.

24) What is static variable?

Ans : Static variables are shared by all instances of a class.

Operators

1) What are operators and what are the various types of operators available in Java?

Ans: Operators are special symbols used in expressions.

The following are the types of operators:

Arithmetic operators,

Assignment operators,

Increment & Decrement operators,

Logical operators,

Biwise operators,

Comparison/Relational operators and

Conditional operators

2) The ++ operator is used for incrementing and the -- operator is used for

decrementing.

a)True

b)False

Ans: a.

3) Comparison/Logical operators are used for testing and magnitude.

a)True

b)False

Ans: a.

4) Character literals are stored as unicode characters.

a)True

b)False

Ans: a.

5) What are the Logical operators?

Ans: OR(|), AND(&), XOR(^) AND NOT(~).

6) What is the % operator?

Ans : % operator is the modulo operator or reminder operator. It returns the reminder of dividing the first operand by second operand.

7) What is the value of 111 % 13?

3

5

7

9

Ans : c.

8) Is &&= a valid operator?

Ans : No.

9) Can a double value be cast to a byte?

Ans : Yes

10) Can a byte object be cast to a double value ?

Ans : No. An object cannot be cast to a primitive value.

11) What are order of precedence and associativity?

Ans : Order of precedence the order in which operators are evaluated in expressions.

Associativity determines whether an expression is evaluated left-right or right-left.

12) Which Java operator is right associativity?

Ans : = operator.

13) What is the difference between prefix and postfix of -- and ++ operators?

Ans : The prefix form returns the increment or decrement operation and returns the value of the increment or decrement operation.

The postfix form returns the current value of all of the expression and then

performs the increment or decrement operation on that value.

14) What is the result of expression 5.45 + "3,2"?

The double value 8.6

The string ""8.6"

The long value 8.

The String "5.453.2"

Ans : d

15) What are the values of x and y ?

x = 5; y = ++x;

Ans : x = 6; y = 6

16) What are the values of x and z?

x = 5; z = x++;

Ans : x = 6; z = 5

Control Statements

1) What are the programming constructs?

Ans: a) Sequential

b) Selection -- if and switch statements

c) Iteration -- for loop, while loop and do-while loop

2) class conditional {

public static void main(String args[]) {

int i = 20;

int j = 55;

int z = 0;

z = i < j ? i : j; // ternary operator

System.out.println("The value assigned is " + z);

}

}

What is output of the above program?

Ans: The value assigned is 20

3) The switch statement does not require a break.

a)True

b)False

Ans: b.

4) The conditional operator is otherwise known as the ternary operator.

a)True

b)False

Ans: a.

5) The while loop repeats a set of code while the condition is false.

a)True

b)False

Ans: b.

6) The do-while loop repeats a set of code atleast once before the condition is tested.

a)True

b)False

Ans: a.

7) What are difference between break and continue?

Ans: The break keyword halts the execution of the current loop and forces control out of the loop.

The continue is similar to break, except that instead of halting the execution of the loop, it starts the next iteration.

8) The for loop repeats a set of statements a certain number of times until a condition is matched.

a)True

b)False

Ans: a.

9) Can a for statement loop indefintely?

Ans : Yes.

10) What is the difference between while statement and a do statement/

Ans : A while statement checks at the beginning of a loop to see whether the next loop iteration should occur.

A do statement checks at the end of a loop to see whether the next iteration of a loop should occur. The do statement will always execute the body of a loop at least once.

Introduction to Classes and Methods

1) Which is used to get the value of the instance variables?

Ans: Dot notation.

2) The new operator creates a single instance named class and returns a

reference to that object.

a)True

b)False

Ans: a.

3) A class is a template for multiple objects with similar features.

a)True

b)False

Ans: a.

4) What is mean by garbage collection?

Ans: When an object is no longer referred to by any variable, Java automatically

reclaims memory used by that object. This is known as garbage collection.

5) What are methods and how are they defined?

Ans: Methods are functions that operate on instances of classes in which they are defined.Objects can communicate with each other using methods and can call methods in other classes.

Method definition has four parts. They are name of the method, type of object or primitive type the method returns, a list of parameters and the body of the method.

A method's signature is a combination of the first three parts mentioned above.

6) What is calling method?

Ans: Calling methods are similar to calling or referring to an instance variable. These methods are accessed using dot notation.

Ex: obj.methodname(param1,param2)

7) Which method is used to determine the class of an object?

Ans: getClass( ) method can be used to find out what class the belongs to. This class is defined in the object class and is available to all objects.

8) All the classes in java.lang package are automatically imported when

a program is compiled.

a)True

b)False

Ans: a.

9) How can class be imported to a program?

Ans: To import a class, the import keyword should be used as shown.;

import classname;

10) How can class be imported from a package to a program?

Ans: import java . packagename . classname (or) import java.package name.*;

11) What is a constructor?

Ans: A constructor is a special kind of method that determines how an object is

initialized when created.

12) Which keyword is used to create an instance of a class?

Ans: new.

13) Which method is used to garbage collect an object?

Ans: finalize ().

14) Constructors can be overloaded like regular methods.

a)True

b)False

Ans: a.

15) What is casting?

Ans: Casting is bused to convert the value of one type to another.

16) Casting between primitive types allows conversion of one primitive type to another.

a)True

b)False

Ans: a.

17) Casting occurs commonly between numeric types.

a)True

b)False

Ans: a.

18) Boolean values can be cast into any other primitive type.

a)True

b)False

Ans: b.

19) Casting does not affect the original object or value.

a)True

b)False

Ans: a.

20) Which cast must be used to convert a larger value into a smaller one?

Ans: Explicit cast.

21) Which cast must be used to cast an object to another class?

Ans: Specific cast.

22) Which of the following features are common to both Java & C++?

A.The class declaration

b.The access modifiers

c.The encapsulation of data & methods with in objects

d.The use of pointers

Ans: a,b,c.

23) Which of the following statements accurately describe the use of access modifiers within a class definition?

a.They can be applied to both data & methods

b.They must precede a class's data variables or methods

c.They can follow a class's data variables or methods

d.They can appear in any order

e.They must be applied to data variables first and then to methods

Ans: a,b,d.

24) Suppose a given instance variable has been declared private.

Can this instance variable be manipulated by methods out side its class?

a.yes

b.no

Ans: b.

25) Which of the following statements can be used to describe a public method?

a.It is accessible to all other classes in the hierarchy

b.It is accessablde only to subclasses of its parent class

c.It represents the public interface of its class

d.The only way to gain access to this method is by calling one of the public class

methods

Ans: a,c.

26) Which of the following types of class members can be part of the internal part of a class?

a.Public instance variables

b.Private instance variables

c.Public methods

d.Private methods

Ans: b,d.

27) You would use the ____ operator to create a single instance of a named class.

a.new

b.dot

Ans: a.

28) Which of the following statements correctly describes the relation between an object and the instance variable it stores?

a.Each new object has its own distinctive set of instance variables

b.Each object has a copy of the instance variables of its class

c.the instance variable of each object are seperate from the variables of other objects

d.The instance variables of each object are stored together with the variables of other objects

Ans: a,b,c.

29) If no input parameters are specified in a method declaration then the declaration will include __.

a.an empty set of parantheses

b.the term void

Ans: a.

30) What are the functions of the dot(.) operator?

a.It enables you to access instance variables of any objects within a class

b.It enables you to store values in instance variables of an object

c.It is used to call object methods

d.It is to create a new object

Ans: a,b,c.

31) Which of the following can be referenced by this variable?

a.The instance variables of a class only

b.The methods of a class only

c.The instance variables and methods of a class

Ans: c.

32) The this reference is used in conjunction with ___methods.

a.static

b.non-static

Ans: b.

33) Which of the following operators are used in conjunction with the this and super references?

a.The new operator

b.The instanceof operator

c.The dot operator

Ans: c.

34) A constructor is automatically called when an object is instantiated

a. true

b. false

Ans: a.

35) When may a constructor be called without specifying arguments?

a. When the default constructor is not called

b. When the name of the constructor differs from that of the class

c. When there are no constructors for the class

Ans: c.

36) Each class in java can have a finalizer method

a. true

b.false

Ans: a.

37) When an object is referenced, does this mean that it has been identified by the finalizer method for garbage collection?

a.yes

b.no

Ans: b.

38) Because finalize () belongs to the java.lang.Object class, it is present in all ___.

a.objects

b.classes

c.methods

Ans: b.

39) Identify the true statements about finalization.

a.A class may have only one finalize method

b.Finalizers are mostly used with simple classes

c.Finalizer overloading is not allowed

Ans: a,c.

40) When you write finalize() method for your class, you are overriding a finalizer

inherited from a super class.

a.true

b.false

Ans: a.

41) Java memory management mechanism garbage collects objects which are no longer referenced

a true

b.false

Ans: a.

42) are objects referenced by a variable candidates for garbage collection when the variable goes out of scope?

a yes

b. no

Ans: a.

43) Java's garbage collector runs as a ___ priority thread waiting for __priority threads to relinquish the processor.

a.high

b.low

Ans: a,b.

44) The garbage collector will run immediately when the system is out of memory

a.true

b.false

Ans: a.

45) You can explicitly drop a object reference by setting the value of a variable whose data type is a reference type to ___

Ans: null

46) When might your program wish to run the garbage collecter?

a. before it enters a compute-intense section of code

b. before it enters a memory-intense section of code

c. before objects are finalized

d. when it knows there will be some idle time

Ans: a,b,d

47) For externalizable objects the class is solely responsible for the external format of its contents

a.true

b.false

Ans: a

48) When an object is stored, are all of the objects that are reachable from that object stored as well?

a.true

b.false

Ans: a

49) The default__ of objects protects private and trancient data, and supports the __ of the classes

a.evolution

b.encoding

Ans: b,a.

50) Which are keywords in Java?

a) NULL

b) sizeof

c) friend

d) extends

e) synchronized

Ans : d and e

51) When must the main class and the file name coincide?

Ans :When class is declared public.

52) What are different modifiers?

Ans : public, private, protected, default, static, trancient, volatile, final, abstract.

53) What are access modifiers?

Ans : public, private, protected, default.

54) What is meant by "Passing by value" and " Passing by reference"?

Ans : objects – pass by referrence

Methods - pass by value

55) Is a class a subclass of itself?

Ans : A class is a subclass itself.

56) What modifiers may be used with top-level class?

Ans : public, abstract, final.

57) What is an example of polymorphism?

Inner class

Anonymous classes

Method overloading

Method overriding

Ans : c

Packages and interface

1) What are packages ? what is use of packages ?

Ans :The package statement defines a name space in which classes are stored.If you omit the package, the classes are put into the default package.

Signature... package pkg;

Use: * It specifies to which package the classes defined in a file belongs to. * Package is both naming and a visibility control mechanism.

2) What is difference between importing "java.applet.Applet" and "java.applet.*;" ?

Ans :"java.applet.Applet" will import only the class Applet from the package java.applet

Where as "java.applet.*" will import all the classes from java.applet package.

3) What do you understand by package access specifier?

Ans : public: Anything declared as public can be accessed from anywhere

private: Anything declared in the private can’t be seen outside of its class.

default: It is visible to subclasses as well as to other classes in the same package.

4) What is interface? What is use of interface?

Ans : It is similar to class which may contain method’s signature only but not bodies.

Methods declared in interface are abstract methods. We can implement many interfaces on a class which support the multiple inheritance.

5) Is it is necessary to implement all methods in an interface?

Ans : Yes. All the methods have to be implemented.

6) Which is the default access modifier for an interface method?

Ans : public.

7) Can we define a variable in an interface ?and what type it should be ?

Ans : Yes we can define a variable in an interface. They are implicitly final and static.

8) What is difference between interface and an abstract class?

Ans : All the methods declared inside an Interface are abstract. Where as abstract class must have at least one abstract method and others may be concrete or abstract.

In Interface we need not use the keyword abstract for the methods.

9) By default, all program import the java.lang package.

True/False

Ans : True

10) Java compiler stores the .class files in the path specified in CLASSPATH

environmental variable.

True/False

Ans : False

11) User-defined package can also be imported just like the standard packages.

True/False

Ans : True

12) When a program does not want to handle exception, the ______class is used.

Ans : Throws

13) The main subclass of the Exception class is _______ class.

Ans : RuntimeException

14) Only subclasses of ______class may be caught or thrown.

Ans : Throwable

15) Any user-defined exception class is a subclass of the _____ class.

Ans : Exception

16) The catch clause of the user-defined exception class should ______ its

Base class catch clause.

Ans : Exception

17) A _______ is used to separate the hierarchy of the class while declaring an

Import statement.

Ans : Package

18) All standard classes of Java are included within a package called _____.

Ans : java.lang

19) All the classes in a package can be simultaneously imported using ____.

Ans : *

20) Can you define a variable inside an Interface. If no, why? If yes, how?

Ans.: YES. final and static

21) How many concrete classes can you have inside an interface?

Ans.: None

22) Can you extend an interface?

Ans.: Yes

23) Is it necessary to implement all the methods of an interface while implementing the interface?

Ans.: No

24) If you do not implement all the methods of an interface while implementing , what specifier should you use for the class ?

Ans.: abstract

25) How do you achieve multiple inheritance in Java?

Ans: Using interfaces.

26) How to declare an interface example?

Ans : access class classname implements interface.

27) Can you achieve multiple interface through interface?

a)True

b) false

Ans : a.

28) Can variables be declared in an interface ? If so, what are the modifiers?

Ans : Yes. final and static are the modifiers can be declared in an interface.

29) What are the possible access modifiers when implementing interface methods?

Ans : public.

30) Can anonymous classes be implemented an interface?

Ans : Yes.

31) Interfaces can’t be extended.

a)True

b)False

Ans : b.

32) Name interfaces without a method?

Ans : Serializable, Cloneble & Remote.

33) Is it possible to use few methods of an interface in a class ? If so, how?

Ans : Yes. Declare the class as abstract.

Exception Handling

1) What is the difference between ‘throw’ and ‘throws’ ?And it’s application?

Ans : Exceptions that are thrown by java runtime systems can be handled by Try and catch blocks. With throw exception we can handle the exceptions thrown by the program itself. If a method is capable of causing an exception that it does not

handle, it must specify this behavior so the callers of the method can guard

against that exception.

2) What is the difference between ‘Exception’ and ‘error’ in java?

Ans : Exception and Error are the subclasses of the Throwable class. Exception class is used for exceptional conditions that user program should catch. With exception class we can subclass to create our own custom exception.

Error defines exceptions that are not excepted to be caught by you program. Example is Stack Overflow.

3) What is ‘Resource leak’?

Ans : Freeing up other resources that might have been allocated at the beginning of a method.

4)What is the ‘finally’ block?

Ans : Finally block will execute whether or not an exception is thrown. If an exception is thrown, the finally block will execute even if no catch statement match the exception. Any time a method is about to return to the caller from inside try/catch block, via an uncaught exception or an explicit return statement, the finally clause is also execute.

5) Can we have catch block with out try block? If so when?

Ans : No. Try/Catch or Try/finally form a unit.

6) What is the difference between the following statements?

Catch (Exception e),

Catch (Error err),

Catch (Throwable t)

Ans :

7) What will happen to the Exception object after exception handling?

Ans : It will go for Garbage Collector. And frees the memory.

8) How many Exceptions we can define in ‘throws’ clause?

Ans : We can define multiple exceptions in throws clause.

Signature is..

type method-name (parameter-list) throws exception-list

9) The finally block is executed when an exception is thrown, even if no catch matches it.

True/False

Ans : True

10) The subclass exception should precede the base class exception when used within the catch clause.

True/False

Ans : True

11) Exceptions can be caught or rethrown to a calling method.

True/False

Ans : True

12) The statements following the throw keyword in a program are not executed.

True/False

Ans : True

13) The toString ( ) method in the user-defined exception class is overridden.

True/False

Ans : True

MULTI THREADING

1) What are the two types of multitasking?

Ans : 1.process-based

2.Thread-based

2) What are the two ways to create the thread?

Ans : 1.by implementing Runnable

2.by extending Thread

3) What is the signature of the constructor of a thread class?

Ans : Thread(Runnable threadob,String threadName)

4) What are all the methods available in the Runnable Interface?

Ans : run()

5) What is the data type for the method isAlive() and this method is

available in which class?

Ans : boolean, Thread

6) What are all the methods available in the Thread class?

Ans : 1.isAlive()

2.join()

3.resume()

4.suspend()

5.stop()

6.start()

7.sleep()

8.destroy()

7) What are all the methods used for Inter Thread communication and what is the class in which these methods are defined?

Ans :1. wait(),notify() & notifyall()

2. Object class

8) What is the mechanisam defind by java for the Resources to be used by only one Thread at a time?

Ans : Synchronisation

9) What is the procedure to own the moniter by many threads?

Ans : not possible

10) What is the unit for 1000 in the below statement?

ob.sleep(1000)

Ans : long milliseconds

11) What is the data type for the parameter of the sleep() method?

Ans : long

12) What are all the values for the following level?

max-priority

min-priority

normal-priority

Ans : 10,1,5

13) What is the method available for setting the priority?

Ans : setPriority()

14) What is the default thread at the time of starting the program?

Ans : main thread

15) The word synchronized can be used with only a method.

True/ False

Ans : False

16) Which priority Thread can prompt the lower primary Thread?

Ans : Higher Priority

17) How many threads at a time can access a monitor?

Ans : one

18) What are all the four states associated in the thread?

Ans : 1. new 2. runnable 3. blocked 4. dead

19) The suspend()method is used to teriminate a thread?

True /False

Ans : False

20) The run() method should necessary exists in clases created as subclass of thread?

True /False

Ans : True

21) When two threads are waiting on each other and can't proceed the programe is said to be in a deadlock?

True/False

Ans : True

22) Which method waits for the thread to die ?

Ans : join() method

23) Which of the following is true?

1) wait(),notify(),notifyall() are defined as final & can be called only from with in a synchronized method

2) Among wait(),notify(),notifyall() the wait() method only throws IOException

3) wait(),notify(),notifyall() & sleep() are methods of object class

1

2

3

1 & 2

1,2 & 3

Ans : D

24) Garbage collector thread belongs to which priority?

Ans : low-priority

25) What is meant by timeslicing or time sharing?

Ans : Timeslicing is the method of allocating CPU time to individual threads in a priority schedule.

26) What is meant by daemon thread? In java runtime, what is it's role?

Ans : Daemon thread is a low priority thread which runs intermittently in the background doing the garbage collection operation for the java runtime system.

Inheritance

1) What is the difference between superclass & subclass?

Ans : A super class is a class that is inherited whereas subclass is a class that does the inheriting.

2) Which keyword is used to inherit a class?

Ans : extends

3) Subclasses methods can access superclass members/ attributes at all times?

True/False

Ans : False

4) When can subclasses not access superclass members?

Ans : When superclass is declared as private.

5) Which class does begin Java class hierarchy?

Ans : Object class

6) Object class is a superclass of all other classes?

True/False

Ans : True

7) Java supports multiple inheritance?

True/False

Ans : False

8) What is inheritance?

Ans : Deriving an object from an existing class. In the other words, Inheritance is the process of inheriting all the features from a class

9) What are the advantages of inheritance?

Ans : Reusability of code and accessibility of variables and methods of the superclass by subclasses.

10) Which method is used to call the constructors of the superclass from the subclass?

Ans : super(argument)

11) Which is used to execute any method of the superclass from the subclass?

Ans : super.method-name(arguments)

12) Which methods are used to destroy the objects created by the constructor methods?

Ans : finalize()

13) What are abstract classes?

Ans : Abstract classes are those for which instances can’t be created.

14) What must a class do to implement an interface?

Ans: It must provide all of the methods in the interface and identify the interface in its implements clause.

15) Which methods in the Object class are declared as final?

Ans : getClass(), notify(), notifyAll(), and wait()

16) Final methods can be overridden.

True/False

Ans : False

17) Declaration of methods as final results in faster execution of the program?

True/False

Ans: True

18) Final variables should be declared in the beginning?

True/False

Ans : True

19) Can we declare variable inside a method as final variables? Why?

Ans : Cannot because, local variable cannot be declared as final variables.

20) Can an abstract class may be final?

Ans : An abstract class may not be declared as final.

21) Does a class inherit the constructors of it's super class?

Ans: A class does not inherit constructors from any of it's super classes.

22) What restrictions are placed on method overloading?

Ans: Two methods may not have the same name and argument list but different return types.

23) What restrictions are placed on method overriding?

Ans : Overridden methods must have the same name , argument list , and return type. The overriding method may not limit the access of the method it overridees.The overriding method may not throw any exceptions that may not be thrown by the overridden method.

24) What modifiers may be used with an inner class that is a member of an outer class?

Ans : a (non-local) inner class may be declared as public, protected, private, static, final or abstract.

25) How this() is used with constructors?

Ans: this() is used to invoke a constructor of the same class

26) How super() used with constructors?

Ans : super() is used to invoke a super class constructor

27) Which of the following statements correctly describes an interface?

a)It's a concrete class

b)It's a superclass

c)It's a type of abstract class

Ans: c

28) An interface contains __ methods

a)Non-abstract

b)Implemented

c)unimplemented

Ans:c

STRING HANDLING

Which package does define String and StringBuffer classes?

Ans : java.lang package.

Which method can be used to obtain the length of the String?

Ans : length( ) method.

How do you concatenate Strings?

Ans : By using " + " operator.

Which method can be used to compare two strings for equality?

Ans : equals( ) method.

Which method can be used to perform a comparison between strings that ignores case differences?

Ans : equalsIgnoreCase( ) method.

What is the use of valueOf( ) method?

Ans : valueOf( ) method converts data from its internal format into a human-readable form.

What are the uses of toLowerCase( ) and toUpperCase( ) methods?

Ans : The method toLowerCase( ) converts all the characters in a string from uppercase to

lowercase.

The method toUpperCase( ) converts all the characters in a string from lowercase to

uppercase.

Which method can be used to find out the total allocated capacity of a StrinBuffer?

Ans : capacity( ) method.

Which method can be used to set the length of the buffer within a StringBuffer object?

Ans : setLength( ).

What is the difference between String and StringBuffer?

Ans : String objects are constants, whereas StringBuffer objects are not.

String class supports constant strings, whereas StringBuffer class supports growable, modifiable strings.

What are wrapper classes?

Ans : Wrapper classes are classes that allow primitive types to be accessed as objects.

Which of the following is not a wrapper class?

String

Integer

Boolean

Character

Ans : a.

What is the output of the following program?

public class Question {

public static void main(String args[]) {

String s1 = "abc";

String s2 = "def";

String s3 = s1.concat(s2.toUpperCase( ) );

System.out.println(s1+s2+s3);

}

}

abcdefabcdef

abcabcDEFDEF

abcdefabcDEF

None of the above

ANS : c.

Which of the following methods are methods of the String class?

delete( )

append( )

reverse( )

replace( )

Ans : d.

Which of the following methods cause the String object referenced by s to be changed?

s.concat( )

s.toUpperCase( )

s.replace( )

s.valueOf( )

Ans : a and b.

String is a wrapper class?

True

False

Ans : b.

17) If you run the code below, what gets printed out?

String s=new String("Bicycle");

int iBegin=1;

char iEnd=3;

System.out.println(s.substring(iBegin,iEnd));

Bic

ic

c) icy
d) error: no method matching substring(int,char)

Ans : b.

18) Given the following declarations

String s1=new String("Hello")

String s2=new String("there");

String s3=new String();

Which of the following are legal operations?

s3=s1 + s2;

s3=s1 - s2;

c) s3=s1 & s2
d) s3=s1 && s2

Ans : a.

19) Which of the following statements are true?

The String class is implemented as a char array, elements are addressed using the stringname[] convention

b) Strings are a primitive type in Java that overloads the + operator for concatenation
c) Strings are a primitive type in Java and the StringBuffer is used as the matching wrapper type
d) The size of a string can be retrieved using the length property.

Ans : b.

EXPLORING JAVA.LANG

java.lang package is automatically imported into all programs.

True

False

Ans : a

What are the interfaces defined by java.lang?

Ans : Cloneable, Comparable and Runnable.

What are the constants defined by both Flaot and Double classes?

Ans : MAX_VALUE,

MIN_VALUE,

NaN,

POSITIVE_INFINITY,

NEGATIVE_INFINITY and

TYPE.

What are the constants defined by Byte, Short, Integer and Long?

Ans : MAX_VALUE,

MIN_VALUE and

TYPE.

What are the constants defined by both Float and Double classes?

Ans : MAX_RADIX,

MIN_RADIX,

MAX_VALUE,

MIN_VALUE and

TYPE.

What is the purpose of the Runtime class?

Ans : The purpose of the Runtime class is to provide access to the Java runtime system.

What is the purpose of the System class?

Ans : The purpose of the System class is to provide access to system resources.

Which class is extended by all other classes?

Ans : Object class is extended by all other classes.

Which class can be used to obtain design information about an object?

Ans : The Class class can be used to obtain information about an object’s design.

Which method is used to calculate the absolute value of a number?

Ans : abs( ) method.

What are E and PI?

Ans : E is the base of the natural logarithm and PI is the mathematical value pi.

Which of the following classes is used to perform basic console I/O?

System

SecurityManager

Math

Runtime

Ans : a.

Which of the following are true?

The Class class is the superclass of the Object class.

The Object class is final.

The Class class can be used to load other classes.

The ClassLoader class can be used to load other classes.

Ans : c and d.

Which of the following methods are methods of the Math class?

absolute( )

log( )

cosine( )

sine( )

Ans : b.

Which of the following are true about the Error and Exception classes?

Both classes extend Throwable.

The Error class is final and the Exception class is not.

The Exception class is final and the Error is not.

Both classes implement Throwable.

Ans : a.

Which of the following are true?

The Void class extends the Class class.

The Float class extends the Double class.

The System class extends the Runtime class.

The Integer class extends the Number class.

Ans : d.

17) Which of the following will output -4.0

System.out.println(Math.floor(-4.7));

System.out.println(Math.round(-4.7));

System.out.println(Math.ceil(-4.7));

d) System.out.println(Math.Min(-4.7));

Ans : c.

18) Which of the following are valid statements

a) public class MyCalc extends Math
b) Math.max(s);
c) Math.round(9.99,1);
d) Math.mod(4,10);

e) None of the above.

Ans : e.

19) What will happen if you attempt to compile and run the following code?

Integer ten=new Integer(10);

Long nine=new Long (9);

System.out.println(ten + nine);

int i=1;

System.out.println(i + ten);

19 followed by 20

19 followed by 11

Error: Can't convert java lang Integer

d) 10 followed by 1

Ans : c.

INPUT / OUTPUT : EXPLORING JAVA.IO

What is meant by Stream and what are the types of Streams and classes of the Streams?

Ans : A Stream is an abstraction that either produces or consumes information.

There are two types of Streams. They are:

Byte Streams : Byte Streams provide a convenient means for handling input and output of bytes.

Character Streams : Character Streams provide a convenient means for handling input and output of characters.

Byte Stream classes : Byte Streams are defined by using two abstract classes. They are:InputStream and OutputStream.

Character Stream classes : Character Streams are defined by using two abstract classes. They are : Reader and Writer.

Which of the following statements are true?

UTF characters are all 8-bits.

UTF characters are all 16-bits.

UTF characters are all 24-bits.

Unicode characters are all 16-bits.

Bytecode characters are all 16-bits.

Ans : d.

Which of the following statements are true?

When you construct an instance of File, if you do not use the filenaming semantics of the local machine, the constructor will throw an IOException.

When you construct an instance of File, if the corresponding file does not exist on the local file system, one will be created.

When an instance of File is garbage collected, the corresponding file on the local file system is deleted.

None of the above.

Ans : a,b and c.

The File class contains a method that changes the current working directory.

True

False

Ans : b.

It is possible to use the File class to list the contents of the current working directory.

True

False

Ans : a.

Readers have methods that can read and return floats and doubles.

True

False

Ans : b.

You execute the code below in an empty directory. What is the result?

File f1 = new File("dirname");

File f2 = new File(f1, "filename");

A new directory called dirname is created in the current working directory.

A new directory called dirname is created in the current working directory. A new file called filename is created in directory dirname.

A new directory called dirname and a new file called filename are created, both in the current working directory.

A new file called filename is created in the current working directory.

No directory is created, and no file is created.

Ans : e.

What is the difference between the Reader/Writer class hierarchy and the

InputStream/OutputStream class hierarchy?

Ans : The Reader/Writer class hierarchy is character-oriented and the InputStream/OutputStream class hierarchy is byte-oriented.

What is an I/O filter?

Ans : An I/O filter is an object that reads from one stream and writes to another, usually altering the data in some way as it is passed from one stream to another.

What is the purpose of the File class?

Ans : The File class is used to create objects that provide access to the files and directories of a local file system.

What interface must an object implement before it can be written to a stream as an object?

Ans : An object must implement the Serializable or Externalizable interface before it can be written to a stream as an object.

What is the difference between the File and RandomAccessFile classes?

Ans : The File class encapsulates the files and directories of the local file system. The RandomAccessFile class provides the methods needed to directly access data contained in any part of a file.

What class allows you to read objects directly from a stream?

Ans : The ObjectInputStream class supports the reading of objects from input streams.

What value does read( ) return when it has reached the end of a file?

Ans : The read( ) method returns – 1 when it has reached the end of a file.

What value does readLine( ) return when it has reached the end of a file?

Ans : The readLine( ) method returns null when it has reached the end of a file.

How many bits are used to represent Unicode, ASCII, UTF-16 and UTF-8 characters?

Ans : Unicode requires 16-bits and ASCII requires 8-bits. Although the ASCII character set uses only 1-bits, it is usually represented as 8-bits. UTF-8 represents characters using 8, 16 and 18-bit patterns. UTF-16 uses 16-bit and larger bit patterns.

Which of the following are true?

The InputStream and OutputStream classes are byte-oriented.

The ObjectInputStream and ObjectOutputStream do not support serialized object input and output.

The Reader and Writer classes are character-oriented.

The Reader and Writer classes are the preferred solution to serialized object output.

Ans : a and c.

Which of the following are true about I/O filters?

Filters are supported on input, but not on output.

Filters are supported by the InputStream/OutputStream class hierarchy, but not by the Reader/Writer class hierarchy.

Filters read from one stream and write to another.

A filter may alter data that is read from one stream and written to another.

Ans : c and d.

Which of the following are true?

Any Unicode character is represented using 16-bits.

7-bits are needed to represent any ASCII character.

UTF-8 characters are represented using only 8-bits.

UTF-16 characters are represented using only 16-bits.

Ans : a and b.

Which of the following are true?

The Serializable interface is used to identify objects that may be written to an output stream.

The Externalizable interface is implemented by classes that control the way in which their objects are serialized.

The Serializable interface extends the Externalizable interface.

The Externalizable interface extends the Serializable interface.

Ans : a, b and d.

Which of the following are true about the File class?

A File object can be used to change the current working directory.

A File object can be used to access the files in the current directory.

When a File object is created, a corresponding directory or file is created in the local file system.

File objects are used to access files and directories on the local file system.

File objects can be garbage collected.

When a File object is garbage collected, the corresponding file or directory is deleted.

Ans : b, d and e.

How do you create a Reader object from an InputStream object?

Use the static createReader( ) method of InputStream class.

Use the static createReader( ) method of Reader class.

Create an InputStreamReader object, passing the InputStream object as an argument to the InputStreamReader constructor.

Create an OutputStreamReader object, passing the InputStream object as an argument to the OutputStreamReader constructor.

Ans : c.

Which of the following are true?

Writer classes can be used to write characters to output streams using different character encodings.

Writer classes can be used to write Unicode characters to output streams.

Writer classes have methods that support the writing of the values of any Java primitive type to output streams.

Writer classes have methods that support the writing of objects to output streams.

Ans : a and b.

The isFile( ) method returns a boolean value depending on whether the file object is a file or a directory.

True.

False.

Ans : a.

Reading or writing can be done even after closing the input/output source.

True.

False.

Ans : b.

The ________ method helps in clearing the buffer.

Ans : flush( ).

The System.err method is used to print error message.

True.

False.

Ans : a.

What is meant by StreamTokenizer?

Ans : StreamTokenizer breaks up InputStream into tokens that are delimited by sets of characters.

It has the constructor : StreamTokenizer(Reader inStream).

Here inStream must be some form of Reader.

What is Serialization and deserialization?

Ans : Serialization is the process of writing the state of an object to a byte stream.

Deserialization is the process of restoring these objects.

30) Which of the following can you perform using the File class?

a) Change the current directory
b) Return the name of the parent directory
c) Delete a file
d) Find if a file contains text or binary information

Ans : b and c.

31)How can you change the current working directory using an instance of the File class called FileName?

FileName.chdir("DirName").

FileName.cd("DirName").

FileName.cwd("DirName").

The File class does not support directly changing the current directory.

Ans : d.

EVENT HANDLING

The event delegation model, introduced in release 1.1 of the JDK, is fully compatible with the

event model.

True

False

Ans : b.

A component subclass that has executed enableEvents( ) to enable processing of a certain kind of event cannot also use an adapter as a listener for the same kind of event.

True

False

Ans : b.

What is the highest-level event class of the event-delegation model?

Ans : The java.util.eventObject class is the highest-level class in the event-delegation hierarchy.

What interface is extended by AWT event listeners?

Ans : All AWT event listeners extend the java.util.EventListener interface.

What class is the top of the AWT event hierarchy?

Ans : The java.awt.AWTEvent class is the highest-level class in the AWT event class hierarchy.

What event results from the clicking of a button?

Ans : The ActionEvent event is generated as the result of the clicking of a button.

What is the relationship between an event-listener interface and an event-adapter class?

Ans : An event-listener interface defines the methods that must be implemented by an event

handler for a particular kind of event.

An event adapter provides a default implementation of an event-listener interface.

In which package are most of the AWT events that support the event-delegation model defined?

Ans : Most of the AWT–related events of the event-delegation model are defined in the

java.awt.event package. The AWTEvent class is defined in the java.awt package.

What is the advantage of the event-delegation model over the earlier event-inheritance model?

Ans : The event-delegation has two advantages over the event-inheritance model. They are :

It enables event handling by objects other than the ones that generate the events. This

allows a clean separation between a component’s design and its use.

It performs much better in applications where many events are generated. This

performance improvement is due to the fact that the event-delegation model does not

have to repeatedly process unhandled events, as is the case of the event-inheritance

model.

What is the purpose of the enableEvents( ) method?

Ans :The enableEvents( ) method is used to enable an event for a particular object.

Which of the following are true?

The event-inheritance model has replaced the event-delegation model.

The event-inheritance model is more efficient than the event-delegation model.

The event-delegation model uses event listeners to define the methods of event-handling classes.

The event-delegation model uses the handleEvent( ) method to support event handling.

Ans : c.

Which of the following is the highest class in the event-delegation model?

java.util.EventListener

java.util.EventObject

java.awt.AWTEvent

java.awt.event.AWTEvent

Ans : b.

When two or more objects are added as listeners for the same event, which listener is first invoked to handle the event?

The first object that was added as listener.

The last object that was added as listener.

There is no way to determine which listener will be invoked first.

It is impossible to have more than one listener for a given event.

Ans : c.

Which of the following components generate action events?

Buttons

Labels

Check boxes

Windows

Ans : a.

Which of the following are true?

A TextField object may generate an ActionEvent.

A TextArea object may generate an ActionEvent.

A Button object may generate an ActionEvent.

A MenuItem object may generate an ActionEvent.

Ans : a,c and d.

Which of the following are true?

The MouseListener interface defines methods for handling mouse clicks.

The MouseMotionListener interface defines methods for handling mouse clicks.

The MouseClickListener interface defines methods for handling mouse clicks.

The ActionListener interface defines methods for handling the clicking of a button.

Ans : a and d.

Suppose that you want to have an object eh handle the TextEvent of a TextArea object t. How should you add eh as the event handler for t?

t.addTextListener(eh);

eh.addTextListener(t);

addTextListener(eh.t);

addTextListener(t,eh);

Ans : a.

What is the preferred way to handle an object’s events in Java 2?

Override the object’s handleEvent( ) method.

Add one or more event listeners to handle the events.

Have the object override its processEvent( ) methods.

Have the object override its dispatchEvent( ) methods.

Ans : b.

Which of the following are true?

A component may handle its own events by adding itself as an event listener.

A component may handle its own events by overriding its event-dispatching method.

A component may not handle oits own events.

A component may handle its own events only if it implements the handleEvent( ) method.

Ans : a and b.

APPLETS

What is an Applet? Should applets have constructors?

Ans : Applet is a dynamic and interactive program that runs inside a Web page

displayed by a Java capable browser. We don’t have the concept of Constructors in Applets.

How do we read number information from my applet’s parameters, given that Applet’s getParameter() method returns a string?

Ans : Use the parseInt() method in the Integer Class, the Float(String) constructor in the

Class Float, or the Double(String) constructor in the class Double.

How can I arrange for different applets on a web page to communicate with each other?

Ans : Name your applets inside the Applet tag and invoke AppletContext’s getApplet()

method in your applet code to obtain references to the other applets on the page.

How do I select a URL from my Applet and send the browser to that page?

Ans : Ask the applet for its applet context and invoke showDocument() on that context object.

Eg. URL targetURL;

String URLString

AppletContext context = getAppletContext();

try{

targetUR L = new URL(URLString);

} catch (Malformed URLException e){

// Code for recover from the exception

}

context. showDocument (targetURL);

Can applets on different pages communicate with each other?

Ans : No. Not Directly. The applets will exchange the information at one meeting place

either on the local file system or at remote system.

How do Applets differ from Applications?

Ans : Appln: Stand Alone

Applet: Needs no explicit installation on local m/c.

Appln: Execution starts with main() method.

Applet: Execution starts with init() method.

Appln: May or may not be a GUI

Applet: Must run within a GUI (Using AWT)

How do I determine the width and height of my application?

Ans : Use the getSize() method, which the Applet class inherits from the Component

class in the Java.awt package. The getSize() method returns the size of the applet as

a Dimension object, from which you extract separate width, height fields.

Eg. Dimension dim = getSize ();

int appletwidth = dim.width ();

8) What is AppletStub Interface?

Ans : The applet stub interface provides the means by which an applet and the browser communicate. Your code will not typically implement this interface.

It is essential to have both the .java file and the .html file of an applet in the same

directory.

True.

False.

Ans : b.

The <PARAM> tag contains two attributes namely _________ and _______.

Ans : Name , value.

Passing values to parameters is done in the _________ file of an applet.

Ans : .html.

12) What tags are mandatory when creating HTML to display an applet

name, height, width

code, name

codebase, height, width

d) code, height, width

Ans : d.

Applet’s getParameter( ) method can be used to get parameter values.

True.

False.

Ans : a.

What are the Applet’s Life Cycle methods? Explain them?

Ans : init( ) method - Can be called when an applet is first loaded.

start( ) method - Can be called each time an applet is started.

paint( ) method - Can be called when the applet is minimized or refreshed.

stop( ) method - Can be called when the browser moves off the applet’s page.

destroy( ) method - Can be called when the browser is finished with the applet.

What are the Applet’s information methods?

Ans : getAppletInfo( ) method : Returns a string describing the applet, its author ,copy

right information, etc.

getParameterInfo( ) method : Returns an array of string describing the applet’s parameters.

All Applets are subclasses of Applet.

True.

False.

Ans : a.

All Applets must import java.applet and java.awt.

True.

False.

Ans : a.

What are the steps involved in Applet development?

Ans : a) Edit a Java source file,

b) Compile your program and

c) Execute the appletviewer, specifying the name of your applet’s source file.

Applets are executed by the console based Java run-time interpreter.

True.

False.

Ans : b.

Which classes and interfaces does Applet class consist?

Ans : Applet class consists of a single class, the Applet class and three interfaces: AppletContext,

AppletStub and AudioClip.

What is the sequence for calling the methods by AWT for applets?

Ans : When an applet begins, the AWT calls the following methods, in this sequence.

init( )

start( )

paint( )

When an applet is terminated, the following sequence of method cals takes place :

stop( )

destroy( )

Which method is used to output a string to an applet?

Ans : drawString ( ) method.

Every color is created from an RGB value.

True.

False

Ans : a.

AWT : WINDOWS, GRAPHICS AND FONTS

How would you set the color of a graphics context called g to cyan?

g.setColor(Color.cyan);

g.setCurrentColor(cyan);

g.setColor("Color.cyan");

g.setColor("cyan’);

g.setColor(new Color(cyan));

Ans : a.

The code below draws a line. What color is the line?

g.setColor(Color.red.green.yellow.red.cyan);

g.drawLine(0, 0, 100,100);

Red

Green

Yellow

Cyan

Black

Ans : d.

What does the following code draw?

g.setColor(Color.black);

g.drawLine(10, 10, 10, 50);

g.setColor(Color.RED);

g.drawRect(100, 100, 150, 150);

A red vertical line that is 40 pixels long and a red square with sides of 150 pixels

A black vertical line that is 40 pixels long and a red square with sides of 150 pixels

A black vertical line that is 50 pixels long and a red square with sides of 150 pixels

A red vertical line that is 50 pixels long and a red square with sides of 150 pixels

A black vertical line that is 40 pixels long and a red square with sides of 100 pixel

Ans : b.

Which of the statements below are true?

A polyline is always filled.

b) A polyline can not be filled.

c) A polygon is always filled.

d) A polygon is always closed

e) A polygon may be filled or not filled

Ans : b, d and e.

What code would you use to construct a 24-point bold serif font?

new Font(Font.SERIF, 24,Font.BOLD);

new Font("SERIF", 24, BOLD");

new Font("BOLD ", 24,Font.SERIF);

new Font("SERIF", Font.BOLD,24);

new Font(Font.SERIF, "BOLD", 24);

Ans : d.

What does the following paint( ) method draw?

Public void paint(Graphics g) {

g.drawString("question #6",10,0);

}

The string "question #6", with its top-left corner at 10,0

A little squiggle coming down from the top of the component, a little way in from the left edge

Ans : b.

What does the following paint( ) method draw?

Public void paint(Graphics g) {

g.drawString("question #6",10,0);

}

A circle at (100, 100) with radius of 44

A circle at (100, 44) with radius of 100

A circle at (100, 44) with radius of 44

The code does not compile

Ans : d.

8)What is relationship between the Canvas class and the Graphics class?

Ans : A Canvas object provides access to a Graphics object via its paint( ) method.

What are the Component subclasses that support painting.

Ans : The Canvas, Frame, Panel and Applet classes support painting.

What is the difference between the paint( ) and repaint( ) method?

Ans : The paint( ) method supports painting via a Graphics object. The repaint( ) method is used

to cause paint( ) to be invoked by the AWT painting method.

What is the difference between the Font and FontMetrics classes?

Ans : The FontMetrics class is used to define implementation-specific properties, such as ascent

and descent, of a Font object.

Which of the following are passed as an argument to the paint( ) method?

A Canvas object

A Graphics object

An Image object

A paint object

Ans : b.

Which of the following methods are invoked by the AWT to support paint and repaint operations?

paint( )

repaint( )

draw( )

redraw( )

Ans : a.

Which of the following classes have a paint( ) method?

Canvas

Image

Frame

Graphics

Ans : a and c.

Which of the following are methods of the Graphics class?

drawRect( )

drawImage( )

drawPoint( )

drawString( )

Ans : a, b and d.

Which Font attributes are available through the FontMetrics class?

ascent

leading

case

height

Ans : a, b and d.

Which of the following are true?

The AWT automatically causes a window to be repainted when a portion of a window has been minimized and then maximized.

The AWT automatically causes a window to be repainted when a portion of a window has been covered and then uncovered.

The AWT automatically causes a window to be repainted when application data is changed.

The AWT does not support repainting operations.

Ans : a and b.

Which method is used to size a graphics object to fit the current size of the window?

Ans : getSize( ) method.

What are the methods to be used to set foreground and background colors?

Ans : setForeground( ) and setBackground( ) methods.

19) You have created a simple Frame and overridden the paint method as follows

public void paint(Graphics g){

g.drawString("Dolly",50,10);

}

What will be the result when you attempt to compile and run the program?

The string "Dolly" will be displayed at the centre of the frame

b) An error at compilation complaining at the signature of the paint method
c) The lower part of the word Dolly will be seen at the top of the form, with the top hidden.
d) The string "Dolly" will be shown at the bottom of the form

Ans : c.

20) Where g is a graphics instance what will the following code draw on the screen.

g.fillArc(45,90,50,50,90,180);

a) An arc bounded by a box of height 45, width 90 with a centre point of 50,50, starting
at an angle of 90 degrees traversing through 180 degrees counter clockwise.

b) An arc bounded by a box of height 50, width 50, with a centre point of 45,90 starting
at an angle of 90 degrees traversing through 180 degrees clockwise.

c) An arc bounded by a box of height 50, width 50, with a top left at coordinates of 45,
90, starting at 90 degrees and traversing through 180 degrees counter clockwise.

d) An arc starting at 45 degrees, traversing through 90 degrees clockwise bounded by a
box of height 50, width 50 with a centre point of 90, 180.

Ans : c.

21) Given the following code
import java.awt.*;
public class SetF extends Frame{
public static void main(String argv[]){
SetF s = new SetF();
s.setSize(300,200);
s.setVisible(true);
}
}
How could you set the frame surface color to pink

a)s.setBackground(Color.pink);
b)s.setColor(PINK);
c)s.Background(pink);
d)s.color=Color.pink

Ans : a.

AWT: CONTROLS, LAYOUT MANAGERS AND MENUS

What is meant by Controls and what are different types of controls?

Ans : Controls are componenets that allow a user to interact with your application.

The AWT supports the following types of controls:

Labels

Push buttons

Check boxes

Choice lists

Lists

Scroll bars

Text components

These controls are subclasses of Component.

You want to construct a text area that is 80 character-widths wide and 10 character-heights tall. What code do you use?

new TextArea(80, 10)

new TextArea(10, 80)

Ans: b.

A text field has a variable-width font. It is constructed by calling new

TextField("iiiii"). What happens if you change the contents of the text field to

"wwwww"? (Bear in mind that is one of the narrowest characters, and w is one of the widest.)

The text field becomes wider.

The text field becomes narrower.

The text field stays the same width; to see the entire contents you will have to scroll by using the ß and à keys.

The text field stays the same width; to see the entire contents you will have to scroll by using the text field’s horizontal scroll bar.

Ans : c.

The CheckboxGroup class is a subclass of the Component class.

True

False

Ans : b.

5) What are the immediate super classes of the following classes?

a) Container class

b) MenuComponent class

c) Dialog class

d) Applet class

e) Menu class

Ans : a) Container - Component

b) MenuComponent - Object

c) Dialog - Window

d) Applet - Panel

e) Menu - MenuItem

6) What are the SubClass of Textcomponent Class?

Ans : TextField and TextArea

7) Which method of the component class is used to set the position and the size of a component?

Ans : setBounds()

8) Which TextComponent method is used to set a TextComponent to the read-only state?

Ans : setEditable()

9) How can the Checkbox class be used to create a radio button?

Ans : By associating Checkbox objects with a CheckboxGroup.

10) What Checkbox method allows you to tell if a Checkbox is checked?

Ans : getState()

11) Which Component method is used to access a component's immediate Container?

getVisible()

getImmediate

getParent()

getContainer

Ans : c.

12) What methods are used to get and set the text label displayed by a Button object?

Ans : getLabel( ) and setLabel( )

13) What is the difference between a Choice and a List?

Ans : A Choice is displayed in a compact form that requires you to pull it down to see the list of available choices. Only one item may be selected from a Choice.

A List may be displayed in such a way that several List items are visible. A List supports the selection of one or more List items.

14) Which Container method is used to cause a container to be laid out and redisplayed?

Ans : validate( )

15) What is the difference between a Scollbar and a Scrollpane?

Ans : A Scrollbar is a Component, but not a Container.

A Scrollpane is a Container and handles its own events and performs its own

scrolling.

16) Which Component subclass is used for drawing and painting?

Ans : Canvas.

17) Which of the following are direct or indirect subclasses of Component?

Button

Label

CheckboxMenuItem

Toolbar

Frame

Ans : a, b and e.

18) Which of the following are direct or indirect subclasses of Container?

Frame

TextArea

MenuBar

FileDialog

Applet

Ans : a,d and e.

19) Which method is used to set the text of a Label object?

setText( )

setLabel( )

setTextLabel( )

setLabelText( )

Ans : a.

20) Which constructor creates a TextArea with 10 rows and 20 columns?

new TextArea(10, 20)

new TextArea(20, 10)

new TextArea(new Rows(10), new columns(20))

new TextArea(200)

Ans : a.

(Usage is TextArea(rows, columns)

21) Which of the following creates a List with 5 visible items and multiple selection enabled?

new List(5, true)

new List(true, 5)

new List(5, false)

new List(false,5)

Ans : a.

[Usage is List(rows, multipleMode)]

22) Which are true about the Container class?

The validate( ) method is used to cause a Container to be laid out and redisplayed.

The add( ) method is used to add a Component to a Container.

The getBorder( ) method returns information about a Container’s insets.

The getComponent( ) method is used to access a Component that is contained in a Container.

Ans : a, b and d.

23) Suppose a Panel is added to a Frame and a Button is added to the Panel. If the Frame’s font is set to 12-point TimesRoman, the Panel’s font is set to 10-point TimesRoman, and the Button’s font is not set, what font will be used to dispaly the Button’s label?

12-point TimesRoman

11-point TimesRoman

10-point TimesRoman

9-point TimesRoman

Ans : c.

A Frame’s background color is set to Color.Yellow, and a Button’s background color is to Color.Blue. Suppose the Button is added to a Panel, which is added to the Frame. What background color will be used with the Panel?

Colr.Yellow

Color.Blue

Color.Green

Color.White

Ans : a.

25) Which method will cause a Frame to be displayed?

show( )

setVisible( )

display( )

displayFrame( )

Ans : a and b.

26) All the componenet classes and container classes are derived from _________ class.

Ans : Object.

27) Which method of the container class can be used to add components to a Panel.

Ans : add ( ) method.

28) What are the subclasses of the Container class?

Ans : The Container class has three major subclasses. They are :

Window

Panel

ScrollPane

29) The Choice component allows multiple selection.

True.

False.

Ans : b.

30) The List component does not generate any events.

True.

False.

Ans : b.

31) Which components are used to get text input from the user.

Ans : TextField and TextArea.

32) Which object is needed to group Checkboxes to make them exclusive?

Ans : CheckboxGroup.

33) Which of the following components allow multiple selections?

Non-exclusive Checkboxes.

Radio buttons.

Choice.

List.

Ans : a and d.

34) What are the types of Checkboxes and what is the difference between them?

Ans : Java supports two types of Checkboxes. They are : Exclusive and Non-exclusive.

In case of exclusive Checkboxes, only one among a group of items can be selected at a time. I f an item from the group is selected, the checkbox currently checked is deselected and the new selection is highlighted. The exclusive Checkboxes are also called as Radio buttons.

The non-exclusive checkboxes are not grouped together and each one can be selected independent of the other.

35) What is a Layout Manager and what are the different Layout Managers available in java.awt and what is the default Layout manager for the panal and the panal subclasses?

Ans: A layout Manager is an object that is used to organize components in a container.

The different layouts available in java.awt are :

FlowLayout, BorderLayout, CardLayout, GridLayout and GridBag Layout.

The default Layout Manager of Panal and Panal sub classes is FlowLayout".

36) Can I exert control over the size and placement of components in my interface?

Ans : Yes.

myPanal.setLayout(null);

myPanal.setbounds(20,20,200,200);

37) Can I add the same component to more than one container?

Ans : No. Adding a component to a container automatically removes it from any previous parent(container).

38) How do I specify where a window is to be placed?

Ans : Use setBounds, setSize, or setLocation methods to implement this.

setBounds(int x, int y, int width, int height)

setBounds(Rectangle r)

setSize(int width, int height)

setSize(Dimension d)

setLocation(int x, int y)

setLocation(Point p)

39) How can we create a borderless window?

Ans : Create an instance of the Window class, give it a size, and show it on the screen.

eg. Frame aFrame = ......

Window aWindow = new Window(aFrame);

aWindow.setLayout(new FlowLayout());

aWindow.add(new Button("Press Me"));

aWindow.getBounds(50,50,200,200);

aWindow.show();

40) Can I create a non-resizable windows? If so, how?

Ans: Yes. By using setResizable() method in class Frame.

41) What is the default Layout Manager for the Window and Window subclasses (Frame,Dialog)?

Ans : BorderLayout().

42) How are the elements of different layouts organized?

Ans : FlowLayout : The elements of a FlowLayout are organized in a top to bottom, left to right fashion.

BorderLayout : The elements of a BorderLayout are organized at the

borders (North, South, East and West) and the center of a

container.

CardLayout : The elements of a CardLayout are stacked, one on top of the other, like a deck of cards.

GridLayout : The elements of a GridLayout are of equal size and are laid out using the square of a grid.

GridBagLayout : The elements of a GridBagLayout are organized according to a grid.However, the elements are of different sizes and may occupy

more than one row or column of the grid. In addition, the rows and columns may have different sizes.

43) Which containers use a BorderLayout as their default layout?

Ans : The Window, Frame and Dialog classes use a BorderLayout as their default layout.

44) Which containers use a FlowLayout as their default layout?

Ans : The Panel and the Applet classes use the FlowLayout as their default layout.

45) What is the preferred size of a component?

Ans : The preferred size of a component size that will allow the component to display normally.

46) Which method is method to set the layout of a container?

startLayout( )

initLayout( )

layoutContainer( )

setLayout( )

Ans : d.

47) Which method returns the preferred size of a component?

getPreferredSize( )

getPreferred( )

getRequiredSize( )

getLayout( )

Ans : a.

48) Which layout should you use to organize the components of a container in a

tabular form?

CardLayout

BorederLayout

FlowLayout

GridLayout

Ans : d.

An application has a frame that uses a Border layout manager. Why is it probably not a good idea to put a vertical scroll bar at North in the frame?

The scroll bar’s height would be its preferred height, which is not likely to be enough.

The scroll bar’s width would be the entire width of the frame, which would be much wider than necessary.

Both a and b.

Neither a nor b. There is no problem with the layout as described.

Ans : c.

What is the default layouts for a applet, a frame and a panel?

Ans : For an applet and a panel, Flow layout is the default layout, whereas Border layout is default layout for a frame.

If a frame uses a Grid layout manager and does not contain any panels, then all the components within the frame are the same width and height.

True

False.

Ans : a.

If a frame uses its default layout manager and does not contain any panels, then all the components within the frame are the same width and height.

True

False.

Ans : b.

With a Border layout manager, the component at Center gets all the space that is left over, after the components at North and South have been considered.

True

False

Ans : b.

An Applet has its Layout Manager set to the default of FlowLayout. What code would be the correct to change to another Layout Manager?

setLayoutManager(new GridLayout());

setLayout(new GridLayout(2,2));

c) setGridLayout(2,2,))
d setBorderLayout();

Ans : b.

55) How do you indicate where a component will be positioned using Flowlayout?

a) North, South,East,West
b) Assign a row/column grid reference
c) Pass a X/Y percentage parameter to the add method
d) Do nothing, the FlowLayout will position the component

Ans :d.

56) How do you change the current layout manager for a container?

a) Use the setLayout method
b) Once created you cannot change the current layout manager of a component
c) Use the setLayoutManager method
d) Use the updateLayout method

Ans :a.

57)When using the GridBagLayout manager, each new component requires a new instance of the GridBagConstraints class. Is this statement true or false?

a) true
b) false

Ans : b.

58) Which of the following statements are true?

a)The default layout manager for an Applet is FlowLayout
b) The default layout manager for an application is FlowLayout
c) A layout manager must be assigned to an Applet before the setSize method is called
d) The FlowLayout manager attempts to honor the preferred size of any components

Ans : a and d.

59) Which method does display the messages whenever there is an item selection or deselection of the CheckboxMenuItem menu?

Ans : itemStateChanged method.

60) Which is a dual state menu item?

Ans : CheckboxMenuItem.

61) Which method can be used to enable/diable a checkbox menu item?

Ans : setState(boolean).

Which of the following may a menu contain?

A separator

A check box

A menu

A button

A panel

Ans : a and c.

Which of the following may contain a menu bar?

A panel

A frame

An applet

A menu bar

A menu

Ans : b

64) What is the difference between a MenuItem and a CheckboxMenuItem?

Ans : The CheckboxMenuItem class extends the MenuItem class to support a menu item

that may be checked or unchecked.

65) Which of the following are true?

A Dialog can have a MenuBar.

MenuItem extends Menu.

A MenuItem can be added to a Menu.

A Menu can be added to a Menu.

Ans : c and d.

Which colour is used to indicate instance methods in the standard "javadoc" format documentation:

1) blue

2) red

3) purple

4) orange

Answer : 2

explain

In JDK 1.1 the variabels, methods and constructors are colour coded to simplifytheir identification.

endExplain

What is the correct ordering for the import, class and package declarations when found in a single file?

1) package, import, class

2) class, import, package

3) import, package, class

4) package, class, import

Answer : 1

explain

This is my explanation for question 2

endExplain

Which methods can be legally applied to a string object?

(Multiple)

1) equals(String)

2) equals(Object)

3) trim()

4) round()

5) toString()

Answer : 1,2,3,5

What is the parameter specification for the public static void main method?

(multiple)

1) String args []

2) String [] args

3) Strings args []

4) String args

Answer : 1,2

What does the zeroth element of the string array passed to the public static void main method contain?

(multiple)

1) The name of the program

2) The number of arguments

3) The first argument if one is present

Answer : 3

Which of the following are Java keywords?

(multiple)

1) goto

2) malloc

3) extends

4) FALSE

Answer : 3

What will be the result of compiling the following code:

public class Test {

public static void main (String args []) {

int age;

age = age + 1;

System.out.println("The age is " + age);

}

}

1) Compiles and runs with no output

2) Compiles and runs printing out The age is 1

3) Compiles but generates a runtime error

4) Does not compile

5) Compiles but generates a compile time error

Answer : 4

Which of these is the correct format to use to create the literal char value a?

(multiple)

1) 'a'

2) "a"

3) new Character(a)

4) \000a

Answer : 1

What is the legal range of a byte integral type?

1) 0 - 65, 535

2) (-128) - 127

3) (-32,768) - 32,767

4) (-256) - 255

Answer : 2

Which of the following is illegal:

1) int i = 32;

2) float f = 45.0;

3) double d = 45.0;

Answer 2

What will be the result of compiling the following code:

public class Test {

static int age;

public static void main (String args []) {

age = age + 1;

System.out.println("The age is " + age);

}

}

1) Compiles and runs with no output

2) Compiles and runs printing out The age is 1

3) Compiles but generates a runtime error

4) Does not compile

5) Compiles but generates a compile time error

Answer : 2

Which of the following are correct?

(multiple)

1) 128 >> 1 gives 64

2) 128 >>> 1 gives 64

3) 128 >> 1 gives -64

4) 128 >>> 1 gives -64

Answer : 1

Which of the following return true?

(multiple)

1) "john" == new String("john")

2) "john".equals("john")

3) "john" = "john"

4) "john".equals(new Button("john"))

Answer : 2

Which of the following do not lead to a runtime error?

(multiple)

1) "john" + " was " + " here"

2) "john" + 3

3) 3 + 5

4) 5 + 5.5

answer 1,2,3,4

Which of the following are so called "short circuit" logical operators?

(multiple)

1) &

2) ||

3) &&

4) |

Answer : 2,3

Which of the following are acceptable?

(multiple)

1) Object o = new Button("A");

2) Boolean flag = true;

3) Panel p = new Frame();

4) Frame f = new Panel();

5) Panel p = new Applet();

Answer : 1,5

What is the result of compiling and running the following code:

public class Test {

static int total = 10;

public static void main (String args []) {

new Test();

}

public Test () {

System.out.println("In test");

System.out.println(this);

int temp = this.total;

if (temp > 5) {

System.out.println(temp);

}

}

}

(multiple)

1) The class will not compile

2) The compiler reports and error at line 2

3) The compiler reports an error at line 9

4) The value 10 is one of the elements printed to the standard output

5) The class compiles but generates a runtime error

Answer : 4

Which of the following is correct:

1) String temp [] = new String {"j" "a" "z"};

2) String temp [] = { "j " " b" "c"};

3) String temp = {"a", "b", "c"};

4) String temp [] = {"a", "b", "c"};

Answer 4

What is the correct declaration of an abstract method that is intended to be public:

1) public abstract void add();

2) public abstract void add() {}

3) public abstract add();

4) public virtual add();

Answer : 1

Under what situations do you obtain a default constructor?

1) When you define any class

2) When the class has no other constructors

3) When you define at least one constructor

Answer : 2

Which of the following can be used to define a constructor for this class, given the following code:

public class Test {

...

}

1) public void Test() {...}

2) public Test() {...}

3) public static Test() {...}

4) public static void Test() {...}

Answer : 2

Which of the following are acceptable to the Java compiler:

(multiple)

1) if (2 == 3) System.out.println("Hi");

2) if (2 = 3) System.out.println("Hi");

3) if (true) System.out.println("Hi");

4) if (2 != 3) System.out.println("Hi");

5) if (aString.equals("hello")) System.out.println("Hi");

Answer : 1,3,4,5

Assuming a method contains code which may raise an Exception (but not a RuntimeException), what is the correct way for a method to indicate that it expects the caller to handle that exception:

1) throw Exception

2) throws Exception

3) new Exception

4) Don't need to specify anything

Answer : 2

What is the result of executing the following code, using the parameters 4 and 0:

public void divide(int a, int b) {

try {

int c = a / b;

} catch (Exception e) {

System.out.print("Exception ");

} finally {

System.out.println("Finally");

}

1) Prints out: Exception Finally

2) Prints out: Finally

3) Prints out: Exception

4) No output

Answer : 1

Which of the following is a legal return type of a method overloading the following method:

public void add(int a) {...}

1) void

2) int

3) Can be anything

Answer : 3

Which of the following statements is correct for a method which is overriding the following method:

public void add(int a) {...}

1) the overriding method must return void

2) the overriding method must return int

3) the overriding method can return whatever it likes

Answer : 1

Given the following classes defined in separate files, what will be the effect of compiling and running this class Test?

class Vehicle {

public void drive() {

System.out.println("Vehicle: drive");

}

}

class Car extends Vehicle {

public void drive() {

System.out.println("Car: drive");

}

}

public class Test {

public static void main (String args []) {

Vehicle v;

Car c;

v = new Vehicle();

c = new Car();

v.drive();

c.drive();

v = c;

v.drive();

}

}

1) Generates a Compiler error on the statement v= c;

2) Generates runtime error on the statement v= c;

3) Prints out:

Vehicle: drive

Car: drive

Car: drive

4) Prints out:

Vehicle: drive

Car: drive

Vehicle: drive

Answer : 3

Where in a constructor, can you place a call to a constructor defined in the super class?

1) Anywhere

2) The first statement in the constructor

3) The last statement in the constructor

4) You can't call super in a constructor

Answer : 2

Which variables can an inner class access from the class which encapsulates it?

(multiple)

1) All static variables

2) All final variables

3) All instance variables

4) Only final instance variables

5) Only final static variables

Answer : 1,2,3

What class must an inner class extend:

1) The top level class

2) The Object class

3) Any class or interface

4) It must extend an interface

Answer 3

In the following code, which is the earliest statement, where the object originally held in e, may be garbage collected:

1. public class Test {

2. public static void main (String args []) {

3. Employee e = new Employee("Bob", 48);

4. e.calculatePay();

5. System.out.println(e.printDetails());

6. e = null;

7. e = new Employee("Denise", 36);

8. e.calculatePay();

9. System.out.println(e.printDetails());

10. }

11. }

1) Line 10

2) Line 11

3) Line 7

4) Line 8

5) Never

Answer : 3

What is the name of the interface that can be used to define a class that can execute within its own thread?

1) Runnable

2) Run

3) Threadable

4) Thread

5) Executable

Answer : 1

What is the name of the method used to schedule a thread for execution?

1) init();

2) start();

3) run();

4) resume();

5) sleep();

Answer : 2

Which methods may cause a thread to stop executing?

(multiple)

1) sleep();

2) stop();

3) yield();

4) wait();

5) notify();

6) notifyAll()

7) synchronized()

Answer : 1,2,3,4

Which of the following would create a text field able to display 10 characters (assuming a fixed size font) displaying the initial string "hello":

1) new TextField("hello", 10);

2) new TextField("hello");

3) new textField(10);

4) new TextField();

Answer : 1

Which of the following methods are defined on the Graphics class:

(multiple)

1) drawLine(int, int, int, int)

2) drawImage(Image, int, int, ImageObserver)

3) drawString(String, int, int)

4) add(Component);

5) setVisible(boolean);

6) setLayout(Object);

Answer : 1,2,3

Which of the following layout managers honours the preferred size of a component:

(multiple)

1) CardLayout

2) FlowLayout

3) BorderLayout

4) GridLayout

Answer : 2

Given the following code what is the effect of a being 5:

public class Test {

public void add(int a) {

loop: for (int i = 1; i < 3; i++){

for (int j = 1; j < 3; j++) {

if (a == 5) {

break loop;

}

System.out.println(i * j);

}

}

}

}

1) Generate a runtime error

2) Throw an ArrayIndexOutOfBoundsException

3) Print the values: 1, 2, 2, 4

4) Produces no output

Answer : 4

What is the effect of issuing a wait() method on an object

1) If a notify() method has already been sent to that object then it has no effect

2) The object issuing the call to wait() will halt until another object sends a notify() or notifyAll() method

3) An exception will be raised

4) The object issuing the call to wait() will be automatically synchronized with any other objects using the receiving object.

Answer : 2

The layout of a container can be altered using which of the following methods:

(multiple)

1) setLayout(aLayoutManager);

2) addLayout(aLayoutManager);

3) layout(aLayoutManager);

4) setLayoutManager(aLayoutManager);

Answer : 1

Using a FlowLayout manager, which is the correct way to add elements to a container:

1) add(component);

2) add("Center", component);

3) add(x, y, component);

4) set(component);

Answer : 1

Given that a Button can generate an ActionEvent which listener would you expect to have to implement, in a class which would handle this event?

1) FocusListener

2) ComponentListener

3) WindowListener

4) ActionListener

5) ItemListener

Answer : 4

Which of the following, are valid return types, for listener methods:

1) boolean

2) the type of event handled

3) void

4) Component

Answer : 3

Assuming we have a class which implements the ActionListener interface, which method should be used to register this with a Button?

1) addListener(*);

2) addActionListener(*);

3) addButtonListener(*);

4) setListener(*);

Answer : 2

In order to cause the paint(Graphics) method to execute, which of the following is the most appropriate method to call:

1) paint()

2) repaint()

3) paint(Graphics)

4) update(Graphics)

5) None - you should never cause paint(Graphics) to execute

Answer : 2

Which of the following illustrates the correct way to pass a parameter into an applet:

1) <applet code=Test.class age=33 width=100 height=100>

2) <param name=age value=33>

3) <applet code=Test.class name=age value=33 width=100 height=100>

4) <applet Test 33>

Answer : 2

Which of the following correctly illustrate how an InputStreamReader can be created:

(multiple)

1) new InputStreamReader(new FileInputStream("data"));

2) new InputStreamReader(new FileReader("data"));

3) new InputStreamReader(new BufferedReader("data"));

4) new InputStreamReader("data");

5) new InputStreamReader(System.in);

Answer : 1,5

What is the permanent effect on the file system of writing data to a new FileWriter("report"), given the file report already exists?

1) The data is appended to the file

2) The file is replaced with a new file

3) An exception is raised as the file already exists

4) The data is written to random locations within the file

Answer : 2

What is the effect of adding the sixth element to a vector created in the following manner:

new Vector(5, 10);

1) An IndexOutOfBounds exception is raised.

2) The vector grows in size to a capacity of 10 elements

3) The vector grows in size to a capacity of 15 elements

4) Nothing, the vector will have grown when the fifth element was added

Answer : 3

What is the result of executing the following code when the value of x is 2:

switch (x) {

case 1:

System.out.println(1);

case 2:

case 3:

System.out.println(3);

case 4:

System.out.println(4);

}

1) Nothing is printed out

2) The value 3 is printed out

3) The values 3 and 4 are printed out

4) The values 1, 3 and 4 are printed out

Answer : 3

What is the result of compiling and running the Second class?

Consider the following example:

class First {

public First (String s) {

System.out.println(s);

}

}

public class Second extends First {

public static void main(String args []) {

new Second();

}

}

1) Nothing happens

2) A string is printed to the standard out

3) An instance of the class First is generated

4) An instance of the class Second is created

5) An exception is raised at runtime stating that there is no null parameter constructor in class First.

6) The class second will not compile as there is no null parameter constructor in the class First

Answer : 6

What is the result of executing the following fragment of code:

boolean flag = false;

if (flag = true) {

System.out.println("true");

} else {

System.out.println("false");

}

1) true is printed to standard out

2) false is printed to standard out

3) An exception is raised

4) Nothing happens

Answer : 1

Consider the following classes. What is the result of compiling and running this class?

public class Test {

public static void test() {

this.print();

}

public static void print() {

System.out.println("Test");

}

public static void main(String args []) {

test();

}

}

(multiple)

1) The string Test is printed to the standard out.

2) A runtime exception is raised stating that an object has not been created.

3) Nothing is printed to the standard output.

4) An exception is raised stating that the method test cannot be found.

5) An exception is raised stating that the variable this can only be used within an instance.

6) The class fails to compile stating that the variable this is undefined.

Answer : 6

Examine the following class definition:

public class Test {

public static void test() {

print();

}

public static void print() {

System.out.println("Test");

}

public void print() {

System.out.println("Another Test");

}

}

What is the result of compiling this class:

1) A successful compilation.

2) A warning stating that the class has no main method.

3) An error stating that there is a duplicated method.

4) An error stating that the method test() will call one or other of the print() methods.

Answer : 3

What is the result of compiling and executing the following Java class:

public class ThreadTest extends Thread {

public void run() {

System.out.println("In run");

suspend();

resume();

System.out.println("Leaving run");

}

public static void main(String args []) {

(new ThreadTest()).start();

}

}

1) Compilation will fail in the method main.

2) Compilation will fail in the method run.

3) A warning will be generated for method run.

4) The string "In run" will be printed to standard out.

5) Both strings will be printed to standard out.

6) Nothing will happen.

Answer : 4

Given the following sequence of Java statements, Which of the following options are true:

1. StringBuffer sb = new StringBuffer("abc");

2. String s = new String("abc");

3. sb.append("def");

4. s.append("def");

5. sb.insert(1, "zzz");

6. s.concat(sb);

7. s.trim();

(multiple)

1) The compiler would generate an error for line 1.

2) The compiler would generate an error for line 2.

3) The compiler would generate an error for line 3.

4) The compiler would generate an error for line 4.

5) The compiler would generate an error for line 5.

6) The compiler would generate an error for line 6.

7) The compiler would generate an error for line 7.

Answer : 4,6

What is the result of executing the following Java class:

import java.awt.*;

public class FrameTest extends Frame {

public FrameTest() {

add (new Button("First"));

add (new Button("Second"));

add (new Button("Third"));

pack();

setVisible(true);

}

public static void main(String args []) {

new FrameTest();

}

}

1) Nothing happens.

2) Three buttons are displayed across a window.

3) A runtime exception is generated (no layout manager specified).

4) Only the "first" button is displayed.

5) Only the "second" button is displayed.

6) Only the "third" button is displayed.

Answer : 6

Consider the following tags and attributes of tags, which can be used with the <AAPLET> and </APPLET> tags?

1. CODEBASE

2. ALT

3. NAME

4. CLASS

5. JAVAC

6. HORIZONTALSPACE

7. VERTICALSPACE

8. WIDTH

9. PARAM

10. JAR

(multiple)

1) line 1, 2, 3

2) line 2, 5, 6, 7

3) line 3, 4, 5

4) line 8, 9, 10

5) line 8, 9

Answer : 1,5

Which of the following is a legal way to construct a RandomAccessFile:

1) RandomAccessFile("data", "r");

2) RandomAccessFile("r", "data");

3) RandomAccessFile("data", "read");

4) RandomAccessFile("read", "data");

Answer : 1

Carefully examine the following code, When will the string "Hi there" be printed?

public class StaticTest {

static {

System.out.println("Hi there");

}

public void print() {

System.out.println("Hello");

}

public static void main(String args []) {

StaticTest st1 = new StaticTest();

st1.print();

StaticTest st2 = new StaticTest();

st2.print();

}

}

1) Never.

2) Each time a new instance is created.

3) Once when the class is first loaded into the Java virtual machine.

4) Only when the static method is called explicitly.

Answer : 3

What is the result of the following program:

public class Test {

public static void main (String args []) {

boolean a = false;

if (a = true)

System.out.println("Hello");

else

System.out.println("Goodbye");

}

}

1) Program produces no output but terminates correctly.

2) Program does not terminate.

3) Prints out "Hello"

4) Prints out "Goodbye"

Answer : 3

Examine the following code, it includes an inner class, what is the result:

public final class Test4 {

class Inner {

void test() {

if (Test4.this.flag); {

sample();

}

}

}

private boolean flag = true;

public void sample() {

System.out.println("Sample");

}

public Test4() {

(new Inner()).test();

}

public static void main(String args []) {

new Test4();

}

}

1) Prints out "Sample"

2) Program produces no output but terminates correctly.

3) Program does not terminate.

4) The program will not compile

Answer : 1

Carefully examine the following class:

public class Test5 {

public static void main (String args []) {

/* This is the start of a comment

if (true) {

Test5 = new test5();

System.out.println("Done the test");

}

/* This is another comment */

System.out.println ("The end");

}

}

1) Prints out "Done the test" and nothing else.

2) Program produces no output but terminates correctly.

3) Program does not terminate.

4) The program will not compile.

5) The program generates a runtime exception.

6) The program prints out "The end" and nothing else.

7) The program prints out "Done the test" and "The end"

Answer : 6

What is the result of compiling and running the following applet:

import java.applet.Applet;

import java.awt.*;

public class Sample extends Applet {

private String text = "Hello World";

public void init() {

add(new Label(text));

}

public Sample (String string) {

text = string;

}

}

It is accessed form the following HTML page:

<html>

<title>Sample Applet</title>

<body>

<applet code="Sample.class" width=200 height=200></applet>

</body>

</html>

1) Prints "Hello World".

2) Generates a runtime error.

3) Does nothing.

4) Generates a compile time error.

Answer : 2

What is the effect of compiling and (if possible) running this class:

public class Calc {

public static void main (String args []) {

int total = 0;

for (int i = 0, j = 10; total > 30; ++i, --j) {

System.out.println(" i = " + i + " : j = " + j);

total += (i + j);

}

System.out.println("Total " + total);

}

}

1) Produce a runtime error

2) Produce a compile time error

3) Print out "Total 0"

4) Generate the following as output:

i = 0 : j = 10

i = 1 : j = 9

i = 2 : j = 8

Total 30

Answer : 3

Utility Package

1) What is the Vector class?

ANSWER : The Vector class provides the capability to implement a growable array of objects.

2) What is the Set interface?

ANSWER : The Set interface provides methods for accessing the elements of a finite mathematical set.Sets do not allow duplicate elements.

3) What is Dictionary class?

ANSWER : The Dictionary class is the abstarct super class of Hashtable and Properties class.Dictionary provides the abstarct functions used to store and retrieve objects by key-value.This class allows any object to be used as a key or value.

4) What is the Hashtable class?

ANSWER : The Hashtable class implements a hash table data structure. A hash table indexes and stores objects in a dictionary using hash codes as the objects' keys. Hash codes are integer values that identify objects.

5) What is the Properties class?

Answer : The properties class is a subclass of Hashtable that can be read from or written to a stream.It also provides the capability to specify a set of default values to be used if a specified key is not found in the table. We have two methods load() and save().

6) What changes are needed to make the following prg to compile?

import java.util.*;

class Ques{

public static void main (String args[]) {

String s1 = "abc";

String s2 = "def";

Vector v = new Vector();

v.add(s1);

v.add(s2);

String s3 = v.elementAt(0) + v.elementAt(1);

System.out.println(s3);

}

}

ANSWER : Declare Ques as public B) Cast v.elementAt(0) to a String

C) Cast v.elementAt(1) to an Object. D) Import java.lang

ANSWER : B) Cast v.elementAt(0) to a String

8) What is the output of the prg.

import java.util.*;

class Ques{

public static void main (String args[]) {

String s1 = "abc";

String s2 = "def";

Stack stack = new Stack();

stack.push(s1);

stack.push(s2);

try{

String s3 = (String) stack.pop() + (String) stack.pop() ;

System.out.println(s3);

}catch (EmptyStackException ex){}

}

}

ANSWER : abcdef B) defabc C) abcabc D) defdef

ANSWER : B) defabc

9) Which of the following may have duplicate elements?

ANSWER : Collection B) List C) Map D) Set

ANSWER : A and B Neither a Map nor a Set may have duplicate elements.

10) Can null value be added to a List?

ANSWER : Yes.A Null value may be added to any List.

11) What is the output of the following prg.

import java.util.*;

class Ques{

public static void main (String args[]) {

HashSet set = new HashSet();

String s1 = "abc";

String s2 = "def";

String s3 = "";

set.add(s1);

set.add(s2);

set.add(s1);

set.add(s2);

Iterator i = set.iterator();

while(i.hasNext())

{

s3 += (String) i.next();

}

System.out.println(s3);

}

}

A) abcdefabcdef B) defabcdefabc C) fedcbafedcba D) defabc

ANSWER : D) defabc. Sets may not have duplicate elements.

12) Which of the following java.util classes support internationalization?

A) Locale B) ResourceBundle C) Country D) Language

ANSWER : A and B . Country and Language are not java.util classes.

13) What is the ResourceBundle?

The ResourceBundle class also supports internationalization.

ResourceBundle subclasses are used to store locale-specific resources that can be loaded by a program to tailor the program's appearence to the paticular locale in which it is being run. Resource Bundles provide the capability to isolate a program's locale-specific resources in a standard and modular manner.

14) How are Observer Interface and Observable class, in java.util package, used?

ANSWER : Objects that subclass the Observable class maintain a list of Observers. When an Observable object is updated it invokes the update() method of each of its observers to notify the observers that it has changed state. The Observer interface is implemented by objects that observe Observable objects.

15) Which java.util classes and interfaces support event handling?

ANSWER : The EventObject class and the EventListener interface support event processing.

16) Does java provide standard iterator functions for inspecting a collection of objects?

ANSWER : The Enumeration interface in the java.util package provides a framework for stepping once through a collection of objects. We have two methods in that interface.

public interface Enumeration {

boolean hasMoreElements();

Object nextElement();

}

17) The Math.random method is too limited for my needs- How can I generate random numbers more flexibly?

ANSWER : The random method in Math class provide quick, convienient access to random numbers, but more power and flexibility use the Random class in the java.util package.

double doubleval = Math.random();

The Random class provide methods returning float, int, double, and long values.

nextFloat() // type float; 0.0 <= value < 1.0

nextDouble() // type double; 0.0 <= value < 1.0

nextInt() // type int; Integer.MIN_VALUE <= value <= Integer.MAX_VALUE

nextLong() // type long; Long.MIN_VALUE <= value <= Long.MAX_VALUE

nextGaussian() // type double; has Gaussian("normal") distribution with mean 0.0 and standard deviation 1.0)

Eg. Random r = new Random();

float floatval = r.nextFloat();

18) How can we get all public methods of an object dynamically?

ANSWER : By using getMethods(). It return an array of method objects corresponding to the public methods of this class.

getFields() returns an array of Filed objects corresponding to the public Fields(variables) of this class.

getConstructors() returns an array of constructor objects corresponding to the public constructors of this class.

JDBC

1) What are the steps involved in establishing a connection?

ANSWER : This involves two steps: (1) loading the driver and (2) making the connection.

2) How can you load the drivers?

ANSWER : Loading the driver or drivers you want to use is very simple and involves just one line of code. If, for example, you want to use the JDBC-ODBC Bridge driver, the following code will load it:

Eg.

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

Your driver documentation will give you the class name to use. For instance, if the class name is jdbc.DriverXYZ , you would load the driver with the following line of code:

Eg.

Class.forName("jdbc.DriverXYZ");

3) What Class.forName will do while loading drivers?

ANSWER : It is used to create an instance of a driver and register it with the DriverManager.

When you have loaded a driver, it is available for making a connection with a DBMS.

4) How can you make the connection?

ANSWER : In establishing a connection is to have the appropriate driver connect to the DBMS. The following line of code illustrates the general idea:

Eg.

String url = "jdbc:odbc:Fred";

Connection con = DriverManager.getConnection(url, "Fernanda", "J8");

5) How can you create JDBC statements?

ANSWER : A Statement object is what sends your SQL statement to the DBMS. You simply create a Statement object and then execute it, supplying the appropriate execute method with the SQL statement you want to send. For a SELECT statement, the method to use is executeQuery. For statements that create or modify tables, the method to use is executeUpdate.

Eg.

It takes an instance of an active connection to create a Statement object. In the following example, we use our Connection object con to create the Statement object stmt :

Statement stmt = con.createStatement();

6) How can you retrieve data from the ResultSet?

ANSWER : Step 1.

JDBC returns results in a ResultSet object, so we need to declare an instance of the class ResultSet to hold our results. The following code demonstrates declaring the ResultSet object rs.

Eg.

ResultSet rs = stmt.executeQuery("SELECT COF_NAME, PRICE FROM COFFEES");

Step2.

String s = rs.getString("COF_NAME");

The method getString is invoked on the ResultSet object rs , so getString will retrieve (get) the value stored in the column COF_NAME in the current row of rs

7) What are the different types of Statements?

ANSWER : 1.Statement (use createStatement method) 2. Prepared Statement (Use prepareStatement method) and 3. Callable Statement (Use prepareCall)

8) How can you use PreparedStatement?

ANSWER : This special type of statement is derived from the more general class, Statement.If you want to execute a Statement object many times, it will normally reduce execution time to use a PreparedStatement object instead.

The advantage to this is that in most cases, this SQL statement will be sent to the DBMS right away, where it will be compiled. As a result, the PreparedStatement object contains not just an SQL statement, but an SQL statement that has been precompiled. This means that when the PreparedStatement is executed, the DBMS can just run the PreparedStatement 's SQL statement without having to compile it first.

Eg.

PreparedStatement updateSales = con.prepareStatement("UPDATE COFFEES SET SALES = ? WHERE COF_NAME LIKE ?");

9) What setAutoCommit does?

ANSWER : When a connection is created, it is in auto-commit mode. This means that each individual SQL statement is treated as a transaction and will be automatically committed right after it is executed. The way to allow two or more statements to be grouped into a transaction is to disable auto-commit mode

Eg.

con.setAutoCommit(false);

Once auto-commit mode is disabled, no SQL statements will be committed until you call the method commit explicitly.

Eg.

con.setAutoCommit(false);

PreparedStatement updateSales = con.prepareStatement(

"UPDATE COFFEES SET SALES = ? WHERE COF_NAME LIKE ?");

updateSales.setInt(1, 50);

updateSales.setString(2, "Colombian");

updateSales.executeUpdate();

PreparedStatement updateTotal = con.prepareStatement("UPDATE COFFEES SET TOTAL = TOTAL + ? WHERE COF_NAME LIKE ?");

updateTotal.setInt(1, 50);

updateTotal.setString(2, "Colombian");

updateTotal.executeUpdate();

con.commit();

con.setAutoCommit(true);

10) How to call a Strored Procedure from JDBC?

ANSWER : The first step is to create a CallableStatement object. As with Statement an and PreparedStatement objects, this is done with an open Connection

object. A CallableStatement object contains a call to a stored procedure;

Eg.

CallableStatement cs = con.prepareCall("{call SHOW_SUPPLIERS}");

ResultSet rs = cs.executeQuery();

11) How to Retrieve Warnings?

ANSWER : SQLWarning objects are a subclass of SQLException that deal with database access warnings. Warnings do not stop the execution of an application, as exceptions do; they simply alert the user that something did not happen as planned.

A warning can be reported on a Connection object, a Statement object (including PreparedStatement and CallableStatement objects), or a ResultSet object. Each of these classes has a getWarnings method, which you must invoke in order to see the first warning reported on the calling object

Eg.

SQLWarning warning = stmt.getWarnings();

if (warning != null) {

System.out.println("\n---Warning---\n");

while (warning != null) {

System.out.println("Message: " + warning.getMessage());

System.out.println("SQLState: " + warning.getSQLState());

System.out.print("Vendor error code: ");

System.out.println(warning.getErrorCode());

System.out.println("");

warning = warning.getNextWarning();

}

}

12) How can you Move the Cursor in Scrollable Result Sets ?

ANSWER : One of the new features in the JDBC 2.0 API is the ability to move a result set's cursor backward as well as forward. There are also methods that let you move the cursor to a particular row and check the position of the cursor.

Eg.

Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,

ResultSet.CONCUR_READ_ONLY);

ResultSet srs = stmt.executeQuery("SELECT COF_NAME, PRICE FROM COFFEES");

The first argument is one of three constants added to the ResultSet API to indicate the type of a ResultSet object: TYPE_FORWARD_ONLY, TYPE_SCROLL_INSENSITIVE , and TYPE_SCROLL_SENSITIVE .

The second argument is one of two ResultSet constants for specifying whether a result set is read-only or updatable: CONCUR_READ_ONLY and CONCUR_UPDATABLE . The point to remember here is that if you specify a type, you must also specify whether it is read-only or updatable. Also, you must specify the type first, and because both parameters are of type int , the compiler will not complain if you switch the order.

Specifying the constant TYPE_FORWARD_ONLY creates a nonscrollable result set, that is, one in which the cursor moves only forward. If you do not specify any constants for the type and updatability of a ResultSet object, you will automatically get one that is TYPE_FORWARD_ONLY and CONCUR_READ_ONLY

13) What’s the difference between TYPE_SCROLL_INSENSITIVE , and TYPE_SCROLL_SENSITIVE?

ANSWER : You will get a scrollable ResultSet object if you specify one of these ResultSet constants.The difference between the two has to do with whether a result set reflects changes that are made to it while it is open and whether certain methods can be called to detect these changes. Generally speaking, a result set that is TYPE_SCROLL_INSENSITIVE does not reflect changes made while it is still open and one that is TYPE_SCROLL_SENSITIVE does. All three types of result sets will make changes visible if they are closed and then reopened

Eg.

Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);

ResultSet srs = stmt.executeQuery("SELECT COF_NAME, PRICE FROM COFFEES");

srs.afterLast();

while (srs.previous()) {

String name = srs.getString("COF_NAME");

float price = srs.getFloat("PRICE");

System.out.println(name + " " + price);

}

14) How to Make Updates to Updatable Result Sets?

ANSWER : Another new feature in the JDBC 2.0 API is the ability to update rows in a result set using methods in the Java programming language rather than having to send an SQL command. But before you can take advantage of this capability, you need to create a ResultSet object that is updatable. In order to do this, you supply the ResultSet constant CONCUR_UPDATABLE to the createStatement method.

Eg.

Connection con = DriverManager.getConnection("jdbc:mySubprotocol:mySubName");

Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,

ResultSet.CONCUR_UPDATABLE);

ResultSet uprs = stmt.executeQuery("SELECT COF_NAME, PRICE FROM COFFEES");

Networking Concepts

1) The API doesn't list any constructors for InetAddress- How do I create an InetAddress instance?

ANSWER : In case of InetAddress the three methods getLocalHost, getByName, getByAllName can be used to create instances.

E.g.

InetAddress add1;

InetAddress add2;

try{

add1 = InetAddress.getByName("java.sun.com");

add2 = InetAddress.getByName("199.22.22.22");

}catch(UnknownHostException e){}

2) Is it possible to get the Local host IP?

ANSWER : Yes. Use InetAddress's getLocalHost method.

3) What's the Factory Method?

ANSWER : Factory methods are merely a convention whereby static methods in a class return an instance of that class. The InetAddress class has no visible constructors. To create an InetAddress object, you have to use one of the available factory methods. In InetAddress the three methods getLocalHost, getByName, getByAllName can be used to create instances of InetAddress.

4) What’s the difference between TCP and UDP?

ANSWER : These two protocols differ in the way they carry out the action of communicating. A TCP protocol establishes a two way connection between a pair of computers, while the UDP protocol is a one-way message sender. The common analogy is that TCP is like making a phone call and carrying on a two-way communication, while UDP is like mailing a letter.

5) What is the Proxy Server?

ANSWER : A proxy server speaks the client side of a protocol to another server. This is often required when clients have certain restrictions on which servers they can connect to. And when several users are hitting a popular web site, a proxy server can get the contents of the web server's popular pages once, saving expensive internetwork transfers while providing faster access to those pages to the clients.

Also, we can get multiple connections for a single server.

6) What are the seven layers of OSI model?

ANSWER : Application, Presentation, Session, Transport, Network, DataLink, Physical Layer.

What Transport Layer does?

ANSWER : It ensures that the mail gets to its destination. If a packet fails to get its destination, it handles the process of notifying the sender and requesting that another packet be sent.

8) What is DHCP?

ANSWER : Dynamic Host Configuration Protocol, a piece of the TCP/IP protocol suite that handles the automatic assignment of IP addresses to clients.

9) What is SMTP?

ANSWER : Simple Mail Transmission Protocol, the TCP/IP Standard for Internet mails. SMTP exchanges mail between servers; contrast this with POP, which transmits mail between a server and a client.

10) In OSI N/w architecture, the dialogue control and token management are responsibilities of...

Answer : Network b) Session c) Application d) DataLink

ANSWER : b) Session Layer.

11) In OSI N/W Architecture, the routing is performed by ______

Answer : Network b) Session c) Application d) DataLink

ANSWER : Answer : Network Layer.

Networking

What is the difference between URL instance and URLConnection instance?

ANSWER : A URL instance represents the location of a resource, and a URLConnection instance represents a link for accessing or communicating with the resource at the location.

2) How do I make a connection to URL?

ANSWER : You obtain a URL instance and then invoke openConnection on it.

URLConnection is an abstract class, which means you can't directly create instances of it using a constructor. We have to invoke openConnection method on a URL instance, to get the right kind of connection for your URL.

Eg. URL url;

URLConnection connection;

try{ url = new URL("...");

conection = url.openConnection();

}catch (MalFormedURLException e) { }

3) What Is a Socket?

A socket is one end-point of a two-way communication link between two programs running on the network. A socket is bound to a port number so that the TCP layer can identify the application that data is destined to be sent.Socket classes are used to represent the connection between a client program and a server program. The java.net package provides two classes--Socket and ServerSocket--which implement the client side of the connection and the server side of the connection, respectively.

What information is needed to create a TCP Socket?

ANSWER : The Local System’s IP Address and Port Number.

And the Remote System's IPAddress and Port Number.

5) What are the two important TCP Socket classes?

ANSWER : Socket and ServerSocket.

ServerSocket is used for normal two-way socket communication. Socket class allows us to read and write through the sockets.

getInputStream() and getOutputStream() are the two methods available in Socket class.

When MalformedURLException and UnknownHostException throws?

ANSWER : When the specified URL is not connected then the URL throw MalformedURLException and If InetAddress’ methods getByName and getLocalHost are unabletoresolve the host name they throwan UnknownHostException.

Servlets

1) What is the servlet?

ANSWER : Servlets are modules that extend request/response-oriented servers, such as Java-enabled web servers. For example, a servlet might be responsible for taking data in an HTML order-entry form and applying the business logic used to update a company's order database.

Servlets are to servers what applets are to browsers. Unlike applets, however, servlets have no graphical user interface.

2) Whats the advantages using servlets than using CGI?

ANSWER : Servlets provide a way to generate dynamic documents that is both easier to write and faster to run. Servlets also address the problem of doing server-side programming with platform-specific APIs: they are developed with the Java Servlet API, a standard Java extension.

3) What are the uses of Servlets?

ANSWER : A servlet can handle multiple requests concurrently, and can synchronize requests. This allows servlets to support systems such as on-line conferencing.

Servlets can forward requests to other servers and servlets.Thus servlets can be used to balance load among several servers that mirror the same content, and to partition a single logical service over several servers, according to task type or organizational boundaries.

4) Which pakage provides interfaces and classes for writing servlets?

ANSWER : javax

5) Whats the Servlet Interfcae?

ANSWER : The central abstraction in the Servlet API is the Servlet interface. All servlets implement this interface, either directly or, more commonly, by extending a class that implements it such as HttpServlet.

Servlets-->Generic Servlet-->HttpServlet-->MyServlet.

The Servlet interface declares, but does not implement, methods that manage the servlet and its communications with clients. Servlet writers provide some or all of these methods when developing a servlet.

6) When a servlet accepts a call from a client, it receives two objects- What are they?

ANSWER : ServeltRequest: Which encapsulates the communication from the client to the server.

ServletResponse: Whcih encapsulates the communication from the servlet back to the client.

ServletRequest and ServletResponse are interfaces defined by the javax.servlet package.

7) What information that the ServletRequest interface allows the servlet access to?

ANSWER : Information such as the names of the parameters passed in by the client, the protocol (scheme) being used by the client, and the names of the remote host that made the request and the server that received it.

The input stream, ServletInputStream.Servlets use the input stream to get data from clients that use application protocols such as the HTTP POST and PUT methods.

8) What information that the ServletResponse interface gives the servlet methods for replying to the client?

ANSWER : It Allows the servlet to set the content length and MIME type of the reply.

Provides an output stream, ServletOutputStream and a Writer through which the servlet can send the reply data.

9) What is the servlet Lifecycle?

ANSWER : Each servlet has the same life cycle:

A server loads and initializes the servlet (init())

The servlet handles zero or more client requests (service())

The server removes the servlet (destroy())

(some servers do this step only when they shut down)

10) How HTTP Servlet handles client requests?

ANSWER : An HTTP Servlet handles client requests through its service method. The service method supports standard HTTP client requests by dispatching each request to a method designed to handle that request. 1

Encapsulation :

Encapsulation is the mechanism that binds together code and the data it manipulates and keeps both safe from outside interference and misuse.

Inheritance:

Inheritance is the process by which one object acquires the properties of another object.

Polymorphism:

Polymorphism is a feature that allows one interface to be used for a general class of actions. The specific action is determined by the exact nature of actions.

Code Blocks:

Two or more statements which is allowed to be grouped into blocks of code is otherwise called as Code Blocks.This is done by enclosing the statements between opening and closing curly braces.

Floating-point numbers:

Floating-point numbers which is also known as real numbers, are used when evaluating expressions that require fractional precision.

Unicode:

Unicode defines a fully international character set that can represent all of the characters found in all human languages. It is a unification of dozens of character sets, such as Latin, Greek, Arabic and many more.

Booleans:

Java has a simple type called boolean, for logical values. It can have only on of two possible values, true or false.

Casting:

A cast is simply an explicit type conversion. To create a conversion between two incompatible types, you must use a cast.

Arrays:

An array is a group of like-typed variables that are referred to by a common name. Arrays offer a convenient means of grouping related information. Arrays of any type can be created and may have one or more dimension.

Relational Operators:

The relational operators determine the relationship that one operand has to the other. They determine the equality and ordering.

11.Short-Circuit Logical Operators:

The secondary versions of the Boolean AND and OR operators are known as short-

circuit logical operators. It is represented by || and &&..

12. Switch:

The switch statement is Java’s multiway branch statement. It provides an easy way to

dispatch execution to different parts of your code based on the value of an

experession.

13. Jump Statements:

Jump statements are the statements which transfer control to another part of your

program. Java Supports three jump statements: break, continue, and return.

14. Instance Variables:

The data, or variable, defined within a class are called instance variable.

JAVA APTITUDE

1.The Java interpreter is used for the execution of the source code.

True

False

Ans: a.

2) On successful compilation a file with the class extension is created.

a) True

b) False

Ans: a.

3) The Java source code can be created in a Notepad editor.

a) True

b) False

Ans: a.

4) The Java Program is enclosed in a class definition.

a) True

b) False

Ans: a.

5) What declarations are required for every Java application?

Ans: A class and the main( ) method declarations.

6) What are the two parts in executing a Java program and their purposes?

Ans: Two parts in executing a Java program are:

Java Compiler and Java Interpreter.

The Java Compiler is used for compilation and the Java Interpreter is used for execution of the application.

7) What are the three OOPs principles and define them?

Ans : Encapsulation, Inheritance and Polymorphism are the three OOPs

Principles.

Encapsulation:

Is the Mechanism that binds together code and the data it manipulates, and keeps both safe from outside interference and misuse.

Inheritance:

Is the process by which one object acquires the properties of another object.

Polymorphism:

Is a feature that allows one interface to be used for a general class of actions.

8) What is a compilation unit?

Ans : Java source code file.

9) What output is displayed as the result of executing the following statement?

System.out.println("// Looks like a comment.");

// Looks like a comment

The statement results in a compilation error

Looks like a comment

No output is displayed

Ans : a.

10) In order for a source code file, containing the public class Test, to successfully compile, which of the following must be true?

It must have a package statement

It must be named Test.java

It must import java.lang

It must declare a public class named Test

Ans : b

11) What are identifiers and what is naming convention?

Ans : Identifiers are used for class names, method names and variable names. An identifier may be any descriptive sequence of upper case & lower case letters,numbers or underscore or dollar sign and must not begin with numbers.

12) What is the return type of program’s main( ) method?

Ans : void

13) What is the argument type of program’s main( ) method?

Ans : string array.

14) Which characters are as first characters of an identifier?

Ans : A – Z, a – z, _ ,$

15) What are different comments?

Ans : 1) // -- single line comment

2) /* --

*/ multiple line comment

3) /** --

*/ documentation

16) What is the difference between constructor method and method?

Ans : Constructor will be automatically invoked when an object is created. Whereas method has to be call explicitly.

17) What is the use of bin and lib in JDK?

Ans : Bin contains all tools such as javac, applet viewer, awt tool etc., whereas Lib

contains all packages and variables.

Data types,variables and Arrays

1) What is meant by variable?

Ans: Variables are locations in memory that can hold values. Before assigning any value to a variable, it must be declared.

2) What are the kinds of variables in Java? What are their uses?

Ans: Java has three kinds of variables namely, the instance variable, the local variable and the class variable.

Local variables are used inside blocks as counters or in methods as temporary variables and are used to store information needed by a single method.

Instance variables are used to define attributes or the state of a particular object and are used to store information needed by multiple methods in the objects.

Class variables are global to a class and to all the instances of the class and are useful for communicating between different objects of all the same class or keeping track of global states.

3) How are the variables declared?

Ans: Variables can be declared anywhere in the method definition and can be initialized during their declaration.They are commonly declared before usage at the beginning of the definition.

Variables with the same data type can be declared together. Local variables must be given a value before usage.

4) What are variable types?

Ans: Variable types can be any data type that java supports, which includes the eight primitive data types, the name of a class or interface and an array.

5) How do you assign values to variables?

Ans: Values are assigned to variables using the assignment operator =.

6) What is a literal? How many types of literals are there?

Ans: A literal represents a value of a certain type where the type describes how that value behaves.

There are different types of literals namely number literals, character literals,

boolean literals, string literals,etc.

7) What is an array?

Ans: An array is an object that stores a list of items.

8) How do you declare an array?

Ans: Array variable indicates the type of object that the array holds.

Ex: int arr[];

9) Java supports multidimensional arrays.

a)True

b)False

Ans: a.

10) An array of arrays can be created.

a)True

b)False

Ans: a.

11) What is a string?

Ans: A combination of characters is called as string.

12) Strings are instances of the class String.

a)True

b)False

Ans: a.

13) When a string literal is used in the program, Java automatically creates instances of the string class.

a)True

b)False

Ans: a.

14) Which operator is to create and concatenate string?

Ans: Addition operator(+).

15) Which of the following declare an array of string objects?

String[ ] s;

String [ ]s:

String[ s]:

String s[ ]:

Ans : a, b and d

16) What is the value of a[3] as the result of the following array declaration?

1

2

3

4

Ans : d

17) Which of the following are primitive types?

byte

String

integer

Float

Ans : a.

18) What is the range of the char type?

0 to 216

0 to 215

0 to 216-1

0 to 215-1

Ans. d

19) What are primitive data types?

Ans : byte, short, int, long

float, double

boolean

char

20) What are default values of different primitive types?

Ans : int - 0

short - 0

byte - 0

long - 0 l

float - 0.0 f

double - 0.0 d

boolean - false

char - null

21) Converting of primitive types to objects can be explicitly.

a)True

b)False

Ans: b.

22) How do we change the values of the elements of the array?

Ans : The array subscript expression can be used to change the values of the elements of the array.

23) What is final varaible?

Ans : If a variable is declared as final variable, then you can not change its value. It becomes constant.

24) What is static variable?

Ans : Static variables are shared by all instances of a class.

Operators

1) What are operators and what are the various types of operators available in Java?

Ans: Operators are special symbols used in expressions.

The following are the types of operators:

Arithmetic operators,

Assignment operators,

Increment & Decrement operators,

Logical operators,

Biwise operators,

Comparison/Relational operators and

Conditional operators

2) The ++ operator is used for incrementing and the -- operator is used for

decrementing.

a)True

b)False

Ans: a.

3) Comparison/Logical operators are used for testing and magnitude.

a)True

b)False

Ans: a.

4) Character literals are stored as unicode characters.

a)True

b)False

Ans: a.

5) What are the Logical operators?

Ans: OR(|), AND(&), XOR(^) AND NOT(~).

6) What is the % operator?

Ans : % operator is the modulo operator or reminder operator. It returns the reminder of dividing the first operand by second operand.

7) What is the value of 111 % 13?

3

5

7

9

Ans : c.

8) Is &&= a valid operator?

Ans : No.

9) Can a double value be cast to a byte?

Ans : Yes

10) Can a byte object be cast to a double value ?

Ans : No. An object cannot be cast to a primitive value.

11) What are order of precedence and associativity?

Ans : Order of precedence the order in which operators are evaluated in expressions.

Associativity determines whether an expression is evaluated left-right or right-left.

12) Which Java operator is right associativity?

Ans : = operator.

13) What is the difference between prefix and postfix of -- and ++ operators?

Ans : The prefix form returns the increment or decrement operation and returns the value of the increment or decrement operation.

The postfix form returns the current value of all of the expression and then

performs the increment or decrement operation on that value.

14) What is the result of expression 5.45 + "3,2"?

The double value 8.6

The string ""8.6"

The long value 8.

The String "5.453.2"

Ans : d

15) What are the values of x and y ?

x = 5; y = ++x;

Ans : x = 6; y = 6

16) What are the values of x and z?

x = 5; z = x++;

Ans : x = 6; z = 5

Control Statements

1) What are the programming constructs?

Ans: a) Sequential

b) Selection -- if and switch statements

c) Iteration -- for loop, while loop and do-while loop

2) class conditional {

public static void main(String args[]) {

int i = 20;

int j = 55;

int z = 0;

z = i < j ? i : j; // ternary operator

System.out.println("The value assigned is " + z);

}

}

What is output of the above program?

Ans: The value assigned is 20

3) The switch statement does not require a break.

a)True

b)False

Ans: b.

4) The conditional operator is otherwise known as the ternary operator.

a)True

b)False

Ans: a.

5) The while loop repeats a set of code while the condition is false.

a)True

b)False

Ans: b.

6) The do-while loop repeats a set of code atleast once before the condition is tested.

a)True

b)False

Ans: a.

7) What are difference between break and continue?

Ans: The break keyword halts the execution of the current loop and forces control out of the loop.

The continue is similar to break, except that instead of halting the execution of the loop, it starts the next iteration.

8) The for loop repeats a set of statements a certain number of times until a condition is matched.

a)True

b)False

Ans: a.

9) Can a for statement loop indefintely?

Ans : Yes.

10) What is the difference between while statement and a do statement/

Ans : A while statement checks at the beginning of a loop to see whether the next loop iteration should occur.

A do statement checks at the end of a loop to see whether the next iteration of a loop should occur. The do statement will always execute the body of a loop at least once.

Introduction to Classes and Methods

1) Which is used to get the value of the instance variables?

Ans: Dot notation.

2) The new operator creates a single instance named class and returns a

reference to that object.

a)True

b)False

Ans: a.

3) A class is a template for multiple objects with similar features.

a)True

b)False

Ans: a.

4) What is mean by garbage collection?

Ans: When an object is no longer referred to by any variable, Java automatically

reclaims memory used by that object. This is known as garbage collection.

5) What are methods and how are they defined?

Ans: Methods are functions that operate on instances of classes in which they are defined.Objects can communicate with each other using methods and can call methods in other classes.

Method definition has four parts. They are name of the method, type of object or primitive type the method returns, a list of parameters and the body of the method.

A method's signature is a combination of the first three parts mentioned above.

6) What is calling method?

Ans: Calling methods are similar to calling or referring to an instance variable. These methods are accessed using dot notation.

Ex: obj.methodname(param1,param2)

7) Which method is used to determine the class of an object?

Ans: getClass( ) method can be used to find out what class the belongs to. This class is defined in the object class and is available to all objects.

8) All the classes in java.lang package are automatically imported when

a program is compiled.

a)True

b)False

Ans: a.

9) How can class be imported to a program?

Ans: To import a class, the import keyword should be used as shown.;

import classname;

10) How can class be imported from a package to a program?

Ans: import java . packagename . classname (or) import java.package name.*;

11) What is a constructor?

Ans: A constructor is a special kind of method that determines how an object is

initialized when created.

12) Which keyword is used to create an instance of a class?

Ans: new.

13) Which method is used to garbage collect an object?

Ans: finalize ().

14) Constructors can be overloaded like regular methods.

a)True

b)False

Ans: a.

15) What is casting?

Ans: Casting is bused to convert the value of one type to another.

16) Casting between primitive types allows conversion of one primitive type to another.

a)True

b)False

Ans: a.

17) Casting occurs commonly between numeric types.

a)True

b)False

Ans: a.

18) Boolean values can be cast into any other primitive type.

a)True

b)False

Ans: b.

19) Casting does not affect the original object or value.

a)True

b)False

Ans: a.

20) Which cast must be used to convert a larger value into a smaller one?

Ans: Explicit cast.

21) Which cast must be used to cast an object to another class?

Ans: Specific cast.

22) Which of the following features are common to both Java & C++?

A.The class declaration

b.The access modifiers

c.The encapsulation of data & methods with in objects

d.The use of pointers

Ans: a,b,c.

23) Which of the following statements accurately describe the use of access modifiers within a class definition?

a.They can be applied to both data & methods

b.They must precede a class's data variables or methods

c.They can follow a class's data variables or methods

d.They can appear in any order

e.They must be applied to data variables first and then to methods

Ans: a,b,d.

24) Suppose a given instance variable has been declared private.

Can this instance variable be manipulated by methods out side its class?

a.yes

b.no

Ans: b.

25) Which of the following statements can be used to describe a public method?

a.It is accessible to all other classes in the hierarchy

b.It is accessablde only to subclasses of its parent class

c.It represents the public interface of its class

d.The only way to gain access to this method is by calling one of the public class

methods

Ans: a,c.

26) Which of the following types of class members can be part of the internal part of a class?

a.Public instance variables

b.Private instance variables

c.Public methods

d.Private methods

Ans: b,d.

27) You would use the ____ operator to create a single instance of a named class.

a.new

b.dot

Ans: a.

28) Which of the following statements correctly describes the relation between an object and the instance variable it stores?

a.Each new object has its own distinctive set of instance variables

b.Each object has a copy of the instance variables of its class

c.the instance variable of each object are seperate from the variables of other objects

d.The instance variables of each object are stored together with the variables of other objects

Ans: a,b,c.

29) If no input parameters are specified in a method declaration then the declaration will include __.

a.an empty set of parantheses

b.the term void

Ans: a.

30) What are the functions of the dot(.) operator?

a.It enables you to access instance variables of any objects within a class

b.It enables you to store values in instance variables of an object

c.It is used to call object methods

d.It is to create a new object

Ans: a,b,c.

31) Which of the following can be referenced by this variable?

a.The instance variables of a class only

b.The methods of a class only

c.The instance variables and methods of a class

Ans: c.

32) The this reference is used in conjunction with ___methods.

a.static

b.non-static

Ans: b.

33) Which of the following operators are used in conjunction with the this and super references?

a.The new operator

b.The instanceof operator

c.The dot operator

Ans: c.

34) A constructor is automatically called when an object is instantiated

a. true

b. false

Ans: a.

35) When may a constructor be called without specifying arguments?

a. When the default constructor is not called

b. When the name of the constructor differs from that of the class

c. When there are no constructors for the class

Ans: c.

36) Each class in java can have a finalizer method

a. true

b.false

Ans: a.

37) When an object is referenced, does this mean that it has been identified by the finalizer method for garbage collection?

a.yes

b.no

Ans: b.

38) Because finalize () belongs to the java.lang.Object class, it is present in all ___.

a.objects

b.classes

c.methods

Ans: b.

39) Identify the true statements about finalization.

a.A class may have only one finalize method

b.Finalizers are mostly used with simple classes

c.Finalizer overloading is not allowed

Ans: a,c.

40) When you write finalize() method for your class, you are overriding a finalizer

inherited from a super class.

a.true

b.false

Ans: a.

41) Java memory management mechanism garbage collects objects which are no longer referenced

a true

b.false

Ans: a.

42) are objects referenced by a variable candidates for garbage collection when the variable goes out of scope?

a yes

b. no

Ans: a.

43) Java's garbage collector runs as a ___ priority thread waiting for __priority threads to relinquish the processor.

a.high

b.low

Ans: a,b.

44) The garbage collector will run immediately when the system is out of memory

a.true

b.false

Ans: a.

45) You can explicitly drop a object reference by setting the value of a variable whose data type is a reference type to ___

Ans: null

46) When might your program wish to run the garbage collecter?

a. before it enters a compute-intense section of code

b. before it enters a memory-intense section of code

c. before objects are finalized

d. when it knows there will be some idle time

Ans: a,b,d

47) For externalizable objects the class is solely responsible for the external format of its contents

a.true

b.false

Ans: a

48) When an object is stored, are all of the objects that are reachable from that object stored as well?

a.true

b.false

Ans: a

49) The default__ of objects protects private and trancient data, and supports the __ of the classes

a.evolution

b.encoding

Ans: b,a.

50) Which are keywords in Java?

a) NULL

b) sizeof

c) friend

d) extends

e) synchronized

Ans : d and e

51) When must the main class and the file name coincide?

Ans :When class is declared public.

52) What are different modifiers?

Ans : public, private, protected, default, static, trancient, volatile, final, abstract.

53) What are access modifiers?

Ans : public, private, protected, default.

54) What is meant by "Passing by value" and " Passing by reference"?

Ans : objects – pass by referrence

Methods - pass by value

55) Is a class a subclass of itself?

Ans : A class is a subclass itself.

56) What modifiers may be used with top-level class?

Ans : public, abstract, final.

57) What is an example of polymorphism?

Inner class

Anonymous classes

Method overloading

Method overriding

Ans : c

Packages and interface

1) What are packages ? what is use of packages ?

Ans :The package statement defines a name space in which classes are stored.If you omit the package, the classes are put into the default package.

Signature... package pkg;

Use: * It specifies to which package the classes defined in a file belongs to. * Package is both naming and a visibility control mechanism.

2) What is difference between importing "java.applet.Applet" and "java.applet.*;" ?

Ans :"java.applet.Applet" will import only the class Applet from the package java.applet

Where as "java.applet.*" will import all the classes from java.applet package.

3) What do you understand by package access specifier?

Ans : public: Anything declared as public can be accessed from anywhere

private: Anything declared in the private can’t be seen outside of its class.

default: It is visible to subclasses as well as to other classes in the same package.

4) What is interface? What is use of interface?

Ans : It is similar to class which may contain method’s signature only but not bodies.

Methods declared in interface are abstract methods. We can implement many interfaces on a class which support the multiple inheritance.

5) Is it is necessary to implement all methods in an interface?

Ans : Yes. All the methods have to be implemented.

6) Which is the default access modifier for an interface method?

Ans : public.

7) Can we define a variable in an interface ?and what type it should be ?

Ans : Yes we can define a variable in an interface. They are implicitly final and static.

8) What is difference between interface and an abstract class?

Ans : All the methods declared inside an Interface are abstract. Where as abstract class must have at least one abstract method and others may be concrete or abstract.

In Interface we need not use the keyword abstract for the methods.

9) By default, all program import the java.lang package.

True/False

Ans : True

10) Java compiler stores the .class files in the path specified in CLASSPATH

environmental variable.

True/False

Ans : False

11) User-defined package can also be imported just like the standard packages.

True/False

Ans : True

12) When a program does not want to handle exception, the ______class is used.

Ans : Throws

13) The main subclass of the Exception class is _______ class.

Ans : RuntimeException

14) Only subclasses of ______class may be caught or thrown.

Ans : Throwable

15) Any user-defined exception class is a subclass of the _____ class.

Ans : Exception

16) The catch clause of the user-defined exception class should ______ its

Base class catch clause.

Ans : Exception

17) A _______ is used to separate the hierarchy of the class while declaring an

Import statement.

Ans : Package

18) All standard classes of Java are included within a package called _____.

Ans : java.lang

19) All the classes in a package can be simultaneously imported using ____.

Ans : *

20) Can you define a variable inside an Interface. If no, why? If yes, how?

Ans.: YES. final and static

21) How many concrete classes can you have inside an interface?

Ans.: None

22) Can you extend an interface?

Ans.: Yes

23) Is it necessary to implement all the methods of an interface while implementing the interface?

Ans.: No

24) If you do not implement all the methods of an interface while implementing , what specifier should you use for the class ?

Ans.: abstract

25) How do you achieve multiple inheritance in Java?

Ans: Using interfaces.

26) How to declare an interface example?

Ans : access class classname implements interface.

27) Can you achieve multiple interface through interface?

a)True

b) false

Ans : a.

28) Can variables be declared in an interface ? If so, what are the modifiers?

Ans : Yes. final and static are the modifiers can be declared in an interface.

29) What are the possible access modifiers when implementing interface methods?

Ans : public.

30) Can anonymous classes be implemented an interface?

Ans : Yes.

31) Interfaces can’t be extended.

a)True

b)False

Ans : b.

32) Name interfaces without a method?

Ans : Serializable, Cloneble & Remote.

33) Is it possible to use few methods of an interface in a class ? If so, how?

Ans : Yes. Declare the class as abstract.

Exception Handling

1) What is the difference between ‘throw’ and ‘throws’ ?And it’s application?

Ans : Exceptions that are thrown by java runtime systems can be handled by Try and catch blocks. With throw exception we can handle the exceptions thrown by the program itself. If a method is capable of causing an exception that it does not

handle, it must specify this behavior so the callers of the method can guard

against that exception.

2) What is the difference between ‘Exception’ and ‘error’ in java?

Ans : Exception and Error are the subclasses of the Throwable class. Exception class is used for exceptional conditions that user program should catch. With exception class we can subclass to create our own custom exception.

Error defines exceptions that are not excepted to be caught by you program. Example is Stack Overflow.

3) What is ‘Resource leak’?

Ans : Freeing up other resources that might have been allocated at the beginning of a method.

4)What is the ‘finally’ block?

Ans : Finally block will execute whether or not an exception is thrown. If an exception is thrown, the finally block will execute even if no catch statement match the exception. Any time a method is about to return to the caller from inside try/catch block, via an uncaught exception or an explicit return statement, the finally clause is also execute.

5) Can we have catch block with out try block? If so when?

Ans : No. Try/Catch or Try/finally form a unit.

6) What is the difference between the following statements?

Catch (Exception e),

Catch (Error err),

Catch (Throwable t)

Ans :

7) What will happen to the Exception object after exception handling?

Ans : It will go for Garbage Collector. And frees the memory.

8) How many Exceptions we can define in ‘throws’ clause?

Ans : We can define multiple exceptions in throws clause.

JAVA APTITUDE

1.The Java interpreter is used for the execution of the source code.

True

False

Ans: a.

2) On successful compilation a file with the class extension is created.

a) True

b) False

Ans: a.

3) The Java source code can be created in a Notepad editor.

a) True

b) False

Ans: a.

4) The Java Program is enclosed in a class definition.

a) True

b) False

Ans: a.

5) What declarations are required for every Java application?

Ans: A class and the main( ) method declarations.

6) What are the two parts in executing a Java program and their purposes?

Ans: Two parts in executing a Java program are:

Java Compiler and Java Interpreter.

The Java Compiler is used for compilation and the Java Interpreter is used for execution of the application.

7) What are the three OOPs principles and define them?

Ans : Encapsulation, Inheritance and Polymorphism are the three OOPs

Principles.

Encapsulation:

Is the Mechanism that binds together code and the data it manipulates, and keeps both safe from outside interference and misuse.

Inheritance:

Is the process by which one object acquires the properties of another object.

Polymorphism:

Is a feature that allows one interface to be used for a general class of actions.

8) What is a compilation unit?

Ans : Java source code file.

9) What output is displayed as the result of executing the following statement?

System.out.println("// Looks like a comment.");

// Looks like a comment

The statement results in a compilation error

Looks like a comment

No output is displayed

Ans : a.

10) In order for a source code file, containing the public class Test, to successfully compile, which of the following must be true?

It must have a package statement

It must be named Test.java

It must import java.lang

It must declare a public class named Test

Ans : b

11) What are identifiers and what is naming convention?

Ans : Identifiers are used for class names, method names and variable names. An identifier may be any descriptive sequence of upper case & lower case letters,numbers or underscore or dollar sign and must not begin with numbers.

12) What is the return type of program’s main( ) method?

Ans : void

13) What is the argument type of program’s main( ) method?

Ans : string array.

14) Which characters are as first characters of an identifier?

Ans : A – Z, a – z, _ ,$

15) What are different comments?

Ans : 1) // -- single line comment

2) /* --

*/ multiple line comment

3) /** --

*/ documentation

16) What is the difference between constructor method and method?

Ans : Constructor will be automatically invoked when an object is created. Whereas method has to be call explicitly.

17) What is the use of bin and lib in JDK?

Ans : Bin contains all tools such as javac, applet viewer, awt tool etc., whereas Lib

contains all packages and variables.

Data types,variables and Arrays

1) What is meant by variable?

Ans: Variables are locations in memory that can hold values. Before assigning any value to a variable, it must be declared.

2) What are the kinds of variables in Java? What are their uses?

Ans: Java has three kinds of variables namely, the instance variable, the local variable and the class variable.

Local variables are used inside blocks as counters or in methods as temporary variables and are used to store information needed by a single method.

Instance variables are used to define attributes or the state of a particular object and are used to store information needed by multiple methods in the objects.

Class variables are global to a class and to all the instances of the class and are useful for communicating between different objects of all the same class or keeping track of global states.

3) How are the variables declared?

Ans: Variables can be declared anywhere in the method definition and can be initialized during their declaration.They are commonly declared before usage at the beginning of the definition.

Variables with the same data type can be declared together. Local variables must be given a value before usage.

4) What are variable types?

Ans: Variable types can be any data type that java supports, which includes the eight primitive data types, the name of a class or interface and an array.

5) How do you assign values to variables?

Ans: Values are assigned to variables using the assignment operator =.

6) What is a literal? How many types of literals are there?

Ans: A literal represents a value of a certain type where the type describes how that value behaves.

There are different types of literals namely number literals, character literals,

boolean literals, string literals,etc.

7) What is an array?

Ans: An array is an object that stores a list of items.

8) How do you declare an array?

Ans: Array variable indicates the type of object that the array holds.

Ex: int arr[];

9) Java supports multidimensional arrays.

Computer Networking technical Aptitude concepts (tutorial)

1.      What are the two types of transmission technology available?

            (i) Broadcast   and      (ii) point-to-point

2.      What is subnet?

            A generic term for section of a large networks usually separated by a bridge or router.

3.      Difference between the communication and transmission.

            Transmission is a physical movement of information and concern issues like bit polarity, synchronisation, clock etc.

            Communication means the meaning full exchange of information between two communication media.

4.      What are the possible ways of data exchange?

            (i) Simplex       (ii) Half-duplex           (iii) Full-duplex.

5.      What is SAP?

            Series of interface points that allow other computers to communicate with the other layers of network protocol stack.

6.      What do you meant by "triple X" in Networks?

The function of PAD (Packet Assembler Disassembler) is described in a document known as X.3. The standard protocol has been defined between the terminal and the PAD, called X.28; another standard protocol exists between hte PAD and the network, called X.29. Together, these three recommendations are often called "triple X"

7.      What is frame relay, in which layer it comes?

Frame relay is a packet switching technology. It will operate in the data link layer.



8.      What is terminal emulation, in which layer it comes?

            Telnet is also called as terminal emulation. It belongs to application layer.

9.      What is Beaconing?

            The process that allows a network to self-repair networks problems. The stations on the network notify the other stations on the ring when they are not receiving the transmissions. Beaconing is used in Token ring and FDDI networks.

10. What is redirector?

            Redirector is software that intercepts file or prints I/O requests and translates them into network requests. This comes under presentation layer.

11. What is NETBIOS and NETBEUI?

            NETBIOS is a programming interface that allows I/O requests to be sent to and received from a remote computer and it hides the networking hardware from applications.

            NETBEUI is NetBIOS extended user interface. A transport protocol designed by microsoft and IBM for the use on small subnets.

12. What is RAID?

            A method for providing fault tolerance by using multiple hard disk drives.

13. What is passive topology?

            When the computers on the network simply listen and receive the signal, they are referred to as passive because they don’t amplify the signal in any way. Example for passive topology - linear bus.

14. What is Brouter?

            Hybrid devices that combine the features of both bridges and routers.

15. What is cladding?

            A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.

16. What is point-to-point protocol

            A communications protocol used to connect computers to remote networking services including Internet service providers.

17. How Gateway is different from Routers?

            A gateway operates at the upper levels of the OSI model and translates information between two completely different network architectures or data formats

18. What is attenuation?

            The degeneration of a signal over distance on a network cable is called attenuation.

19. What is MAC address?

            The address for a device as it is identified at the Media Access Control (MAC) layer in the network architecture. MAC address is usually stored in ROM on the network adapter card and is unique.

20. Difference between bit rate and baud rate.

            Bit rate is the number of bits transmitted during one second whereas baud rate refers to the number of signal units per second that are required to represent those bits.

baud rate = bit rate / N

where N is no-of-bits represented by each signal shift.

Notes & E-papers for Computer Courses

Follow us on facebook

Pages

Bannerad

Popular Posts

Blogroll

About

Aptitude

C Questions Aptitude

C,C++ Questions Aptitude Part 1

C++ Aptitude Questions Part 2

Relational Database management system or Data base Management System Aptitude

Data Structure Aptitude Questions

Networking Aptitude concepts

JAVA APTITUDE Tutorial

Computer Networking technical Aptitude concepts (tutorial)

0 comments:

Post a Comment

Labels

Blogger templates

Blogger news

Blog Archive