Keep Only the Highest Set Bit

Code

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

uint16_t highest_set_bit(uint16_t n) {
    if (n == 0) return 0;
    n |= (n >> 1);
    n |= (n >> 2);
    n |= (n >> 4);
    n |= (n >> 8);
    return (n + 1) >> 1;
}

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

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

Solving Approach