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 val = 0;
    uint8_t pos = 0;
    for (int i = 0; i < 31; i += 2){
        if (((reg >> i) & 1)){
            val |= (1 << pos);
            ++pos;
        }
    }
    return val;
}

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