Question

What should be the output of this C program?

int main()
{
    int x=1,y=1,z;
    if (z=(y>0)) x=5;
    printf("%d %d",x,z);
    return 0;
}

As expected, the output is X is 5 and Z is 1. This is because when expression y>0 is evaluated it is true and so on and so forth. Now the problem is in this program:

int main()
{
    int x,y;
    for (y=1;(x=y)<10;y++)
    ;

    printf("%d %d",x,y);
    return 0;
}

should not the output be an infinite loop? Reason being, (x=y) will always return true(1), which is always less than 10?

Answer 1

No, (x=y) returns the new value after setting x to y’s value.

However, (x==y) returns 1 if they are equal, and 0 if not.