Keep Only the Highest Set Bit

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

// Complete the function
uint16_t highest_set_bit(uint16_t reg) {
    int pos = 16;
    do {
        pos -= 1;
    } while (((1<<pos & reg) == 0) && (pos > 0));
    uint16_t mask = 1<<pos;
    return reg & mask;
}

int main() {
    uint16_t reg;
    scanf("%hu", &reg);

    uint16_t result = highest_set_bit(reg);
    printf("%hu", result);
    return 0;
}