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 even = reg & 0x55555555;
    int i = 0;
    int j = 0;
    uint16_t final = 0;
    while (i < 32 && j < 16) {
        if (even & (1 << i)) {
            final |= (1 << j);
        }
        i += 2;
        j++;
    }
    return final;
}

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