31. Rotate Left in an 8-bit Register

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

uint8_t rotate_left(uint8_t reg, uint8_t n) {
    // Your code here

    uint8_t mark = 0;
    for(int k = 0 ; k < (8-n) ; k++)
        mark |= (1<<k);
    uint8_t tmp = (reg>>(8-n)) & mark;
    uint8_t res = (reg<<n) | tmp;

    return res;
}

int main() {
    uint8_t reg, n;
    scanf("%hhu %hhu", &reg, &n);
    printf("%u", rotate_left(reg, n));
    return 0;
}