Extract Even Bits Only from 32-bit Register

Code

#include <stdio.h>
#include <stdint.h>

uint32_t extract_even_bits(uint32_t reg) {
    // Your code here
    uint16_t res = 0;

    for (uint32_t pos = 0; pos < 31; pos += 2) {
        int mask = 1 & (reg >> pos); 
        res |= mask << (pos/2);
    }

    return res;
}

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

Solving Approach