C MCQs - 1

What does the sizeof operator return in C?

a) Size of a variable in bytes
b) Size of a datatype in bytes
c) Size of a pointer in bytes
d) Size of the code segment in bytes

Answer: b) Size of a datatype in bytes

Which keyword is used to define a constant in C?

a) const
b) constant
c) define
d) var

Answer: a) const

What will be the output of the following code?

#include <stdio.h>
int main() {
    int x = 5;
    int y = 10;
    int z = x + y;
    printf("%d\n", z);
    return 0;
}

a) 15
b) 5
c) 10
d) Compiler error

Answer: a) 15

Which one of the following is the correct way to declare a pointer in C?

a) int ptr;
b) int ptr;
c) int ptr;
d) pointer int;

*Answer: a) int ptr;

What is the value of x after the following code is executed?

int x = 10;
int *ptr = &x;
*ptr = 20;

a) 10
b) 20
c) Undefined
d) Compiler error

Answer: b) 20

What does the strcmp() function do in C?

a) Copies one string to another
b) Compares two strings
c) Concatenates two strings
d) Searches for a substring in a string

Answer: b) Compares two strings

What does the malloc() function do in C?

a) Allocates memory on the stack
b) Allocates memory on the heap
c) Frees memory
d) Resizes memory

Answer: b) Allocates memory on the heap

Which header file is required for using dynamic memory allocation functions in C?

a) <stdio.h>
b) <stdlib.h>
c) <math.h>
d) <ctype.h>

Answer: b) <stdlib.h>

What is the purpose of the break statement in C?

a) To exit a loop
b) To skip the current iteration of a loop
c) To branch unconditionally
d) To terminate the program

Answer: a) To exit a loop

Which one of the following is a valid way to declare a multi-dimensional array in C?

a) int arr[5][];
b) int arr[][];
c) int arr[][5];
d) int arr[][];

Answer: c) int arr[][5];