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 result = 0;
    for(int i = 0; i < 32; i+=2) {
        uint8_t mask = (reg >> i) & 1;
        result |= (mask << (i / 2));
    }
    return result;
}

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