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 count = 0;

    while(reg > 0) {

        count += reg & 1;   // Check last bit
        reg = reg >> 1;     // Right shift
    }

    return count;
}

int main() {

    uint8_t reg;

    scanf("%hhu", &reg);

    printf("%u", count_set_bits(reg));

    return 0;
}