22. Extract Even Bits Only from 32-bit Register

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

uint32_t extract_even_bits(uint32_t reg) {
    int ret=0;
    for(int i=15;i>=0;i--){
        ret|=(reg>>i*2&1)<<i;
    }
    return ret;
}

int main() {
    uint32_t reg;
    scanf("%u", &reg);
    printf("%u", extract_even_bits(reg));
    return 0;
}