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 res=0;
    for (int i=0; i<16; i++)
    {
        if (((reg>>(2*i))&1)==1) 
        res |= (1<<i);
        else
        res  &=(~(1<<i)) ;
        //res = (((reg>>(2*i))&1)==1) ? (res | (1<<(i))) : (res & (~(1<<(i))));
    }
    return res ;
}

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