Keep Only the Highest Set Bit

Code

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

// Complete the function
uint16_t highest_set_bit(uint16_t reg) {
    // Find the first 1 bit
    int r_bit_index = 0;
    for(int i=15;i>=0;i--){
        if((reg >> i) & 1){
            r_bit_index = i;
            break;
        }
    }
    // make mask
    uint16_t mask = (1 << r_bit_index) - 1;

    // apply 
    return reg & ~mask;
}

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

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

Solving Approach