22. Extract Even Bits Only from 32-bit Register

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

uint32_t extract_even_bits(uint32_t reg) {
    // Your code here
    int ans = 0;
    while(reg > 0) {
        if(reg & 1){
            ans <<= 1;
            ans ^= 1;
        }
        reg >>= 2;
    }
    
    return ans;
}

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