Extract Even Bits Only from 32-bit Register

Code

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

uint32_t extract_even_bits(uint32_t reg) {
    uint32_t res=0,a;
    int b=0;
    for(int i=0;i<32;i=i+2){
        a=0;
        a=1&(reg>>i);
        res=res|(a<<b);
        b++;
    }
    return res;
}

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

Solving Approach