Keep Only the Highest Set Bit

Code

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

// Complete the function
uint16_t highest_set_bit(uint16_t reg) {
    int firstOne = -1; 
    for (int i=0; i < 16; i++) {
        if (reg & ( 1 << i)) {
            firstOne = i;
        }
    }
    if (firstOne == -1) return 0;
    for (int i=0; i < firstOne; i++) {
        reg &= ~(1 << i);
    }
    return reg;
}

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

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

Solving Approach