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
    uint32_t result = 0U;
    uint32_t mask = (reg & 0x55555555);
    int i=0;
    while(mask){
        result |= (mask & 0x1)<<i;
        mask = mask>>2;
        i++;
    }
    return result;
}

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