Keep Only the Highest Set Bit

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

// Complete the function
uint16_t highest_set_bit(uint16_t reg) {
    uint16_t mask = (uint16_t)(1U << 15);

    for (int i = 0; i < 16; i++) {
        if (reg & mask) {
            return mask;
        }
        mask >>= 1;
    }
    // No bits were set. 
    return 0;
}

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

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