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 out = 0;
    uint32_t mask1 = 1;
    uint32_t mask2 = 1;
    int pos = 0;
    while(pos < 16)
    {
        if (reg & mask1) out |= mask2;
        mask1 = mask1 << 2;
        mask2 = mask2 << 1;
        pos++;
    }
    return out;
}

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

Solving Approach