Extract Even Bits Only from 32-bit Register

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

uint32_t extract_even_bits(uint32_t reg) {
    uint16_t res = 0;
    for(uint8_t i=0;i<16;i++)
    {
        reg <<= 1;
        res <<= 1;
        res |= ((reg & (1<<31)) ? 1 : 0);
        reg <<= 1;
    }
    return res;
}

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