Keep Only the Highest Set Bit

Code

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

uint16_t highest_set_bit(uint16_t reg) {
    if (reg == 0) return 0;

    reg |= reg >> 1;
    reg |= reg >> 2;
    reg |= reg >> 4;
    reg |= reg >> 8;

    return reg & ~(reg >> 1);
}

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

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

Solving Approach