34. Count Set Bits in an 8-bit Register

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

uint8_t count_set_bits(uint8_t reg) {
    // Your code here
    int i;
    uint8_t count = 0;
    for (i = 0; i < sizeof(reg)*8; i++) {
        if ((reg >> i) & 1U) count ++;
    }

    return count;
}

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