Extract Even Bits Only from 32-bit Register

Code

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

uint32_t extract_even_bits(uint32_t reg) {
    int i;
    uint32_t ret = 0;
    for (i = 30; i >= 0; i -= 2) {
        ret |= ((reg & (1 << i)) >> i);
        if (i)
            ret <<= 1;
    }
    return ret;
}

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

Solving Approach