34. Count Set Bits in an 8-bit Register

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

uint8_t count_set_bits(uint8_t reg) {
    int counter = 0;
    while (reg > 0){ //brian kernighan's algorithm.
        reg = reg & (reg -1);
        counter ++;
    }
    return counter;
}

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