Question

I know this is stupid but I’m a quiet a noob in a programming world here is my code.

This one works perfectly:

#include <stdio.h>

int main() {

    float x = 3153600000 ;

    printf("%f", x);

    return 0;
}

But this one has a problem:

#include <stdio.h>

int main() {

    float x = 60 * 60 * 24 * 365 * 100 ;

    printf("%f", x);

    return 0;
} 

So 60 * 60 * 24 * 365 * 100 is 3153600000 right ??? if yes then why does it produced different results ??? I got the overflow in the second one it printed “-1141367296.000000” as a result. Could anyone tell me why ?

Answer 1

You’re multiplying integers, then putting the result in a float. By that time, it has already overflowed.

Try float x = 60.0f * 60.0f * 24.0f * 365.0f * 100.0f;. You should get the result you want.