Keep Only the Highest Set Bit

Code

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

// Complete the function
uint16_t highest_set_bit(uint16_t reg) {
    if (reg == 0) return 0;
    uint8_t index = 0;
    uint16_t hb = reg;
    while(!(hb & 0x8000)){
        hb <<= 1;
        index++;
    }
    reg = (1 << (15- index));
    return reg;
}

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

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