Keep Only the Highest Set Bit

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

uint16_t highest_set_bit(uint16_t reg) {
  
  for(uint8_t i=1; i<16;i*=2){
    reg|=(reg>>i);
  }
  return reg^(reg>>1);
    
}

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

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