What am I doing wrong here?
$ cat size.c
#include<stdio.h>
#include<math.h>
int main() {
printf ("sizeof unsigned int = %d bytes.\n", sizeof(unsigned int));
printf ("sizeof unsigned long long = %d bytes.\n", sizeof(unsigned long long));
printf ("max unsigned int = %d\n", (int)(pow(2, 32) - 1));
printf ("max unsigned long long = %lld\n", (unsigned long long)(pow(2, 64) - 1));
}
$ gcc size.c -o size
$ ./size
sizeof unsigned int = 4 bytes.
sizeof unsigned long long = 8 bytes.
max unsigned int = 2147483647
max unsigned long long = -1
$
I am expecting 18446744073709551615
as output instead of a -1
at the last line.
Okay, I completely missed that I was getting the wrong value for 232 - 1, which should have been 4294967295, not 2147483647. Things make more sense now.
Just don't suppose that it has a certain value use ULLONG_MAX