GATE CSE 2017 Set 2 | Question: 54

Question

Consider the following C program.

#include<stdio.h>
int main () {
    int m=10;
    int n, n1;
    n=++m;
    n1=m++;
    n--;
    --n1;
    n-=n1;
    printf(“%d”, n);
    return 0;
}

The output of the program is ______

Comments

#include<stdio.h>                            

int main () {

    int m=10;                                        \\m=10

    int n, n1;

    n=++m;                                          \\n=11,m=11

    n1=m++;                                        \\n1=11,m=12

    n--;                                                   \\n=10

    --n1;                                                 \\n1=10

    n-=n1;                                             \\n=10-10=0

    printf(“%d”, n);                              \\0

    return 0;

}

output is 0.

Answer 1

• $m = 10; \quad \; \qquad \qquad \overset{m}{\boxed{10}}$
• $n=\text{++}m; \qquad\qquad  \overset{n}{\boxed{11}}  \quad\overset{m}{\boxed{11}}$
• $n1=m\text{++}; \; \;\quad \qquad  \overset{n1}{\boxed{11}}  \quad\overset{m}{\boxed{12}}$
• $n\text{ --}; \; \; \;\qquad \qquad \qquad \overset{n}{\boxed{10}}$
• $\text{-- }n1; \;\qquad \qquad \qquad \overset{n1}{\boxed{10}}$
• $n\text{ -= }n1; \; \;\;\; \qquad \qquad \overset{n}{\boxed{0}} \quad(\because n = n-n1 = 10-10=0)$

So, 

printf("%d", n); // prints 0.

Hence, answer is 0.

Answer 2

0 is answer

Answer 3

yes correct ans is 0

Answer 4

Final answer is expected to be zero.

Correct me if i am wong!!