Keep Only the Highest Set Bit

Code

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


uint16_t highest_set_bit(uint16_t reg) {
// If reg is 0 return it
    if (reg == 0) return 0;

// Fill all bits to the right with 1s
    for( int i=1; i<=8; i*=2) reg |= (reg >> i);
    
// Isolate the highest bit
    return reg - (reg >> 1);

}

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

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

Solving Approach