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 count = 0;
    int check = 0;
    uint16_t test = 0;

    if(reg == 0){
        return reg;
    }
    else{
        while (!check){
            test = (reg << count) | (reg >> (sizeof(reg) * 8 - count));
            check = ((test & 32768) == 32768)? 1 : 0;
            count++;
        }
        reg &= (32768 >> (count - 1));
        return reg;
    }
}

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

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

Solving Approach