Computer Science MCQs | Computer Science Multiple Choice Questions with Answers

Questions
1 Consider a set A = {1, 2, 3, …….., 1000}. How many members of A shall be divisible by 3 or by 5 or by both 3 and 5 ?
A 533
B 599
C 467
D 66

Answer: Option [C]
2 A certain tree has two vertices of degree 4, one vertex of degree 3 and one vertex of degree 2. If the other vertices have degree 1, how many vertices are there in the graph ?
A 5
B n – 3
C 20
D 11

Answer: Option [D]
3 A computer program selects an integer in the set {k : 1 ≤ k ≤ 10,00,000} at random and prints out the result. This process is repeated 1 million times. What is the probability that the value k = 1 appears in the printout atleast once ?
A 0.5
B 0.704
C 0.632121
D 0.68

Answer: Option [C]
4 If we define the functions f, g and h that map R into R by : f(x) = x4, g(x) = x2 + 1, h(x) = x2 + 72, then the value of the composite functions ho(gof) and (hog)of are given as
A x8 – 71 and x8 – 71
B x8 – 73 and x8 – 73
C x8 + 71 and x8 + 71
D x8 + 73 and x8 + 73

Answer: Option [D]
5 The BCD adder to add two decimal digits needs minimum of
A 6 full adders and 2 half adders
B 5 full adders and 3 half adders
C 4 full adders and 3 half adders
D 5 full adders and 2 half adders

Answer: Option [D]
6 The Excess-3 decimal code is a self-complementing code because
A The binary sum of a code and its 9’s complement is equal to 9.
B It is a weighted code.
C Complement can be generated by inverting each bit pattern.
D The binary sum of a code and its 10’s complement is equal to 9.

Answer: Option [B]
7 How many PUSH and POP operations will be needed to evaluate the following expression by reverse polish notation in a stack machine (A ∗ B) + (C ∗ D/E) ?
A 4 PUSH and 3 POP instructions
B 5 PUSH and 4 POP instructions
C 6 PUSH and 2 POP instructions
D 5 PUSH and 3 POP instructions

Answer: Option [B]
8 The range of representable normalized numbers in the floating point binary fractional representation in a 32-bit word with 1-bit sign, 8-bit excess 128 biased exponent and 23-bit mantissa is
A 2–128 to (1 – 2–23) × 2127
B (1 – 2–23) × 2–127 to 2128
C (1 – 2–23) × 2–127 to 223
D 2–129 to (1 – 2–23) × 2127

Answer: Option [D]
9 The size of the ROM required to build an 8-bit adder/subtractor with mode control, carry input, carry output and two’s complement overflow output is given as
A 216 × 8
B 218 × 10
C 216 × 10
D 218 × 8

Answer: Option [B]
10 What will be the output of the following ‘C’ code ? main ( ) { int x = 128; printf (“\n%d”, 1 + x ++); }
A 128
B 129
C 130
D 131

Answer: Option [B]
11 What does the following expression means ? char ∗(∗(∗ a[N]) ( )) ( );
A a pointer to a function returning array of n pointers to function returning character pointers
B a function return array of N pointers to functions returning pointers to characters
C an array of n pointers to function returning pointers to characters
D an array of n pointers to function returning pointers to functions returning pointers to characters

Answer: Option [A]
12 Which of the following is not a member of class ?
A Static function
B Friend function
C Const function
D Virtual function

Answer: Option [B]
13 When an array is passed as parameter to a function, which of the following statements is correct ?
A The function can change values in the original array
B In C, parameters are passed by value, the function cannot change the original value in the array
C It results in compilation error when the function tries to access the elements in the array
D Results in a run time error when the function tries to access the elements in the array

Answer: Option [A]
14 Which of the following differentiates between overloaded functions and overridden functions ?
A Overloading is a dynamic or runtime binding and overridden is a static or compile time binding
B Overloading is a static or compile time binding and overriding is dynamic or runtime binding
C Redefining a function in a friend class is called overloading, while redefining a function in a derived class is called as overridden function
D Redefining a function in a derived class is called function overloading, while redefining a function in a friend class is called function overriding

Answer: Option [B]
15 Division operation is ideally suited to handle queries of the type :
A customers who have no account in any of the branches in Delhi
B customers who have an account at all branches in Delhi
C customers who have an account in atleast one branch in Delhi
D customers who have only joint account in any one branch in Delhi

Answer: Option [B]
16 Which of the following is true ? I. Implementation of self-join is possible in SQL with table alias. II. Outer-join operation is basic operation in relational algebra. III. Natural join and outer join operations are equivalent
A I and II are correct
B II and III are correct
C Only III is correct
D Only I is correct

Answer: Option [D]
17 What kind of mechanism is to be taken into account for converting a weak entity set into strong entity set in entity-relationship diagram ?
A Generalization
B Aggregation
C Specialization
D Adding suitable attributes

Answer: Option [D]
18 The best normal form of relation scheme R(A, B, C, D) along with the set of functional dependencies F = {AB → C, AB → D, C → A, D → B} is
A Boyce-Codd Normal form
B Third Normal form
C Second Normal form
D First Normal form

Answer: Option [B]
19 Identify the minimal key for relational scheme R(A, B, C, D, E) with functional dependencies F = {A → B, B → C, AC → D}
A A
B AE
C BE
D CE| b

Answer: Option [A]
20 Convert the following infix expression into its equivalent post fix expression (A + B^ D) / (E – F) + G
A ABD^ + EF – / G+
B ABD + ^EF – / G+
C ABD + ^EF / – G+
D ABD^ + EF / – G+

Answer: Option [A]
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