Why does rand() % 7 always return 0?

This seems to be a really strange issue:

This is my code:

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[])
{
    @autoreleasepool {
        srand((unsigned int)time(NULL));
        int newRandomNumber = 0;
        newRandomNumber = rand() % 7;
        NSLog(@"%d", rand() % 7); //This prints out what I expected
        NSLog(@"newRandomNumber = %d", newRandomNumber); // This always prints out 0!
    }
    return 0;
}

If I replace that one line that says

newRandomNumber = rand() % 7

with

newRandomNumber = rand() % 8

everything works perfectly. Why is that the case?