Suraku Academy | C Language Loop Statement MCQs & PYQs Bank

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Loop Control Statements : Solved MCQs and PYQs

This section contains carefully selected MCQs and Previous Year Questions with explanations to help students understand concepts and prepare effectively for examinations, interviews, and competitive tests.

Topics Covered

Loops for Loop while Loop do-while Loop Nested Loops Infinite Loops break continue goto Loop Control

Q: 1

Assume that p and q are non-zero positive integers, the following program segment will perform—

while(p!=0)
{
    if(p>q)
        p=p-q;
    else
        q=q-p;
    printf(“%d”,p);

}

A

Subtract small number from large number

B

Computer GCD of the given numbers

C

Computer LCM of the given numbers

D

The loop will run infinitely

Explanation

Option D

The program is trying to reduce the numbers p and q by repeatedly subtracting the smaller one from the bigger one. This looks like the Euclidean method for finding the GCD, but there is a mistake in the loop condition. The loop only checks while(p != 0), so it keeps running as long as p is not zero.

When q becomes zero (which will always happen before p does), the subtraction stops changing the value of p because p = p - 0 will always give the same p. This means the program gets stuck, and the loop keeps running forever without ending.

So, instead of calculating the GCD, this program will go into an infinite loop. The correct way would be to stop when either p or q becomes zero, i.e., use while(p != 0 && q != 0).

Q: 2What will be the output of the following C code in GCC compiler?
#include<stdio.h>
int main()
{
   int a = 5, i = 0;
   for(;i<3;a++,i++){}
   printf(“%d”,a++);
   return 0;
}

A

5

B

6

C

7

D

8

Explanation

Option D

The loop executes 3 times, incrementing both a and i in each iteration. After the loop ends, the value of a becomes 8. The statement printf("%d", a++); prints the current value of a, which is 8. Since it is a post-increment, a is increased to 9 after printing, but this updated value is not displayed.

Q: 3If we want to execute loop statement at least one time even if the condition false initially then we use which loop?

A

for

B

while

C

do while

D

It is not possible

Explanation

Option C

Loops are used to repeat a block of code. The main difference between loops is when the condition is checked.

Some loops check the condition before executing the loop body called entry-control loop. The while and for loops are kind of entry-control loop.
Some loops check the condition after executing the loop body called exit-control loop. The do-while loop is kind of exit-control loop.

In exit-control loop the body is executed at least once, even if the condition is false at the beginning.

Q: 4In C language the break statement can be used for?

A

Exit from function.

B

Exit from if statement.

C

Exit from file.

D

Exit from loop.

Explanation

Option D

In C language, the break statement is a control statement used to immediately stop execution of certain program blocks. It is mainly used to come out of a loop or a switch statement when a specific condition is met.

Q: 5Looping is a process in which set of statements are executed __________ for a finite or infinite number of times.

A

Commonly

B

Repeatedly

C

Mutually

D

Theoretically

Explanation

Option B

Looping is a process in which a set of statements are executed repeatedly for a finite or infinite number of times, until a specific condition is met.
This repetition allows programs to automate tasks and efficiently handle large amounts of data or repeated actions.

Q: 6What is the control flow graph for the following code fragment?
while (a>b)
{
b=b-1;
b=b*a;
}
c=a+b

A

B

C

D

Explanation

Option A

Q: 7What is the output of the following C program?
#include<stdio.h>
void main()
{
int n;
for (n=9;n!=0;n--)
printf("%d ",n--);
}

A

9 8 7 6 5 4 3 2 1

B

9 7 5 3 1

C

Infinite Loop

D

9 7 5 3

Explanation

Option C

The loop variable n is decremented twice in each iteration, once inside printf(n--) and once in the for loop (n--). When n reaches 1, it becomes 0 and then −1, so the condition n != 0 is always true afterward. Since n never becomes 0 again, the loop runs infinitely.

Q: 8Consider the code segment:
#include<stdio.h>
#include<unistd.h>
int main()
{
   int i,n;
   for(i=1;i<n;i++)
   {
       if(fork() == 0)
           printf(“CHILD ”);
   }
   printf(“OS ”);
   return 0;
}
Number of times CHILD and OS are printed?

A

2^n and 2^n

B

2^(n-1) and 2^(n-1)

C

2^(n-1)-1 and 2^(n-1)

D

2^n and 2^(n-1)

Explanation

Option C

Q: 9What will be the output of the following program segment?
int i=0;
int sum=0;
for(i=1;i<11;i++)
{
sum=sum+i;
}
printf(sum);

A

55

B

66

C

45

D

35

Explanation

Option A

The program initializes sum to 0 and starts a for loop with i=1, where the condition i < 11 ensures that the loop runs from 1 to 10. During each iteration, the value of i is added to sum, gradually calculating the total sum of numbers from 1 to 10.
Iteration Process:

Value of ‘i'	sum=sum+i	Updated sum
1	0+1	1
2	1+2	3
3	3+3	6
4	6+4	10
5	10+5	15
6	15+6	21
7	21+7	28
8	28+8	36
9	36+9	45
10	45+10	55

After the loop ends, sum = 55. So, printf(sum); prints 55.

Q: 10In the following C program, how many times will the string "Suraku Academy" be printed?
#include <stdio.h>
void main()
{
int i=1024;
for (; i ; i>>=1)
printf("Suraku Academy");
}

A

10

B

11

C

Infinite Time

D

Compile-Time Error

Explanation

Option B

In C, any non-zero value is treated as true in a loop condition. Here, i is initialized to 1024. The loop condition is simply i, so the loop runs as long as i is not zero.
In each iteration, i>>=1 performs a right shift, which divides i by 2. Thus, the values of i become 1024, 512, 256, 128, 64, 32, 16, 8, 4, 2, and 1. That makes 11 non-zero values, so "Suraku Academy" is printed 11 times. When i becomes 0, the loop terminates.

Showing 10 / 23 Questions

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