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
    int out = 0;
    int i = 0;
    int j = 0;
    int mask = 0;
    for(i = 0; i<=30;){
        mask = 1 << i;
        out |= (((reg&mask)>>i))<<j;
        i += 2;
        ++j;
    }
    return out;
}

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

Solving Approach