Why sizeof(int) is not greater than -1?

Question

this is my C code : why is the output "False " ?????

why 4 > -1???

code :

#include <stdio.h>

int main() {
    if (sizeof(int) > -1)
        printf("True");
    else
        printf("False");
    return 0;
}

Because `sizeof(int)` yields `4` usually and `-1` is casted to `unsigned int` which yields `0x7FFFFFFF` — πάντα ῥεῖ, Jun 28 '14 at 12:35
-1 not the real code (`main` must have a function result type). — Cheers and hth. - Alf, Jun 28 '14 at 12:55
Usually I'm not countervoting, but I see no reason here to downvote. It's a dupe nothing more, nothing less (even it's a hard to find one for a new user). — πάντα ῥεῖ, Jun 28 '14 at 13:00
[Why is −1 > sizeof(int)?](http://stackoverflow.com/q/3100365/995714) — phuclv, Nov 11 '16 at 07:03

score 11 · Answer 1 · answered Jun 28 '14 at 12:35

11

Because sizeof(int) is unsigned. So -1 is converted to a large unsigned value.

answered Jun 28 '14 at 12:35

MTilsted

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score 4 · Answer 2 · answered Jun 28 '14 at 12:36

Because sizeof yields a value of type size_t which is an unsigned type. In > expression usual arithmetic conversions will convert -1 to an unsigned type which is the type of the > result. The resulting value will be a huge positive value.

To get the expected behavior use:

(int) sizeof (int) > -1

Why sizeof(int) is not greater than -1?

2 Answers2

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