34. Count Set Bits in an 8-bit Register

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

uint8_t count_set_bits(uint8_t reg) {
    uint8_t sum = 0;

    for (int i = 0; i < 8; i++) {
        sum += (reg & (1 << i)) != 0;
    }

    return sum;
}

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