Loop Question 6

What will be output of following c code?

#include<stdio.h>

int main(){

    int i=1;

    for(i=0;i=-1;i=1) {

         printf("%d ",i);

         if(i!=1) break;

    }

    return 0;

}

EXPLANATION

Output: -1

Explanation:

Initial value of variable i is 1.

First iteration:

For loop initial value: i = 0

For loop condition: i = -1 . Since -1 is non- zero number. So loop condition true. Hence printf function will print value of variable i i.e. -1

Since variable i is not equal to 1. So, if condition is true. Due to break keyword program control will come out of the for loop.

Loop Question 5

What will be output of following c code?

#include<stdio.h>

int main(){

    static int i;

    for(++i;++i;++i) {

         printf("%d ",i);

         if(i==4) break;

    }

    return 0;

}

EXPLANATION

Output: 24

Explanation:

Default value of static int variable in c is zero. So, initial value of variable i = 0

First iteration:

For loop starts value: ++i i.e. i = 0 + 1 = 1

For loop condition: ++i i.e. i = 1 + 1 = 2 i.e. loop condition is true. Hence printf statement will print 2

Loop incrimination: ++I i.e. i = 2 + 1 =3

Second iteration:

For loop condition: ++i i.e. i = 3 + 1 = 4 i.e. loop condition is true. Hence printf statement will print 4.

Since is equal to for so if condition is also true. But due to break keyword program control will come out of the for loop.

Loop Question 4

What will be output of following c code?

#include<stdio.h>

int main(){

    int i,j;

    i=j=2,3;

    while(--i&&j++)

         printf("%d %d",i,j);

    return 0;

}

EXPLANATION

Output: 13

Explanation:

Initial value of variable

i = 2

j = 2

Consider the while condition : --i && j++

In first iteration:

--i && j++

= 1 && 2 //In c any non-zero number represents true.

= 1 (True)

So while loop condition is true. Hence printf function will print value of i = 1 and j = 3 (Due to post increment operator)

In second iteration:

--i && j++

= 0 && 3  //In c zero represents false

= 0  //False

So while loop condition is false. Hence program control will come out of the for loop.

Loop Question 3

What will be output of following c code?

#include<stdio.h>

int main(){

    int x=011,i;

    for(i=0;i<x;i+=3){

         printf("Start ");

         continue;

         printf("End");

    }

    return 0;

}

EXPLANATION

Output: Start Start Start

Explantion:

011 is octal number. Its equivalent decimal value is 9.

So, x = 9

First iteration:

i = 0

i < x i.e. 0 < 9  i.e. if loop condition is true.

Hence printf statement will print: Start

Due to continue keyword program control will come at the beginning of the for loop and value of variable i will be:

i += 3

i = i + 3 = 3

Second iteration:

i = 3

i < x i.e. 3 < 9 i.e. if loop condition is true.

Hence printf statement will print: Start

Due to continue keyword program control will come at the beginning of the for loop and value of variable i will be:

i += 3

i = i + 3 = 6

Third iteration:

i = 3

i < x i.e. 6 < 9 i.e. if loop condition is true.

Hence printf statement will print: Start

Due to continue keyword program control will come at the beginning of the for loop and value of variable i will be:

i += 3

i = i + 3 = 9

fourth iteration:

i = 6

i < x i.e. 9 < 9 i.e. if loop condition is false.

Hence program control will come out of the for loop.

Loop Question 2:

What will be output of following c code?

        

#include<stdio.h>

int main(){

    int i=2,j=2;

    while(i+1?--i:j++)

         printf("%d",i);

    return 0;

}

EXPLANATION

Output: 1

Explanation:

Consider the while loop condition: i + 1 ? -- i : ++j

In first iteration:

i + 1 = 3 (True)

So ternary operator will return -–i i.e. 1

In c 1 means true so while condition is true. Hence printf statement will print 1

In second iteration:

i+ 1 = 2 (True)

So ternary operator will return -–i i.e. 0

In c zero means false so while condition is false. Hence program control will come out of the while loop.