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;
    // Solution 1:
    // uint16_t len = 0;
    // for(uint16_t i = 0; i < 16; i ++){
    //     uint8_t flag = ((reg >> i) & 0x1);
    //     if(flag){
    //         len = i;
    //     }
    // }
    // return reg &= (0x1 <<len);

    // Solution 2:
    uint16_t res = 1U << 15;
    while((reg & res) == 0) {
        res>>=1;
    }
    return res;
}

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

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

Solving Approach