Rotate a 32-bit number left in C Solution, output & explanation

#include <stdint.h>
#include <stdio.h>

uint32_t rotl(uint32_t x, unsigned n) {
    n &= 31;                                        /* rotating by 32 = rotating by 0 */
    return n ? (x << n) | (x >> (32 - n)) : x;      /* avoid the undefined shift by 32 */
}

int main(void) {
    printf("0x%08X 0x%08X 0x%08X\n",
           (unsigned) rotl(0x12345678u, 8), (unsigned) rotl(0x80000001u, 1), (unsigned) rotl(0xABCDu, 32));
    return 0;
}

0x34567812 0x00000003 0x0000ABCD