Keep Only the Highest Set Bit

Code

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

// Complete the function
uint16_t highest_set_bit(uint16_t reg) {
    // Your logic here
    int ptr = 15;
    int index = -1;
    while(ptr>=0&&index==-1){
        int temp = reg | (1<<ptr);
        if(temp ==  reg){
            index = ptr;
        }
        else{
            ptr--;
        }
    }
    for(int i = index-1;i>=0;i--){
        reg&=~(1<<i);
    }
    if(index==-1)return 0;
    return reg;
}

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

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

Solving Approach