22. Extract Even Bits Only from 32-bit Register

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

uint32_t extract_even_bits(uint32_t reg) {
    
    uint32_t res = 1&reg;
    int i = 1;
    while(reg!=0){
        reg = reg>>2;
        res = res|((reg&1)<<i++);
    }
    return res;
}

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