Extract Even Bits Only from 32-bit Register

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

uint32_t extract_even_bits(uint32_t reg) {
    int a = 0,b=0,c=0;
    for(int i=0;i<32;i++)
    {
        if(i%2==0)
        {
            if((1<<i)&reg)
            {
                b |= 1<<c;
                c++;
                //a |= ((b)|1);
            } 
            else{
                b |= 0<<c;
                c++;
                //a |= ((b)|0);
            }
        }
        
    }
    return b;
}

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

Solving Approach