Keep Only the Highest Set Bit

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

// Complete the function
uint16_t highest_set_bit(uint16_t reg) 
{
   int mask=0x8000;
   if(reg==0)return 0;
   while(mask>0)
   {
        if(reg &mask)
        return mask;
        else
        mask=mask>>1;
   }
}

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

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