Extract Even Bits Only from 32-bit Register

Code

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

uint32_t extract_even_bits(uint32_t reg) {
    // Your code here
    int bit=31;
    int val=0;
    int pos=15;
    while(bit>=0)
    {
        if(bit%2==0)
        {
            int a=0;
            a=reg>>bit&1;
            if(a==0)
            {
                val&=~(1<<pos);
            }
            else
            val|=1<<pos;
            pos--;
        }
        bit--;
    }
    return val;
}

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

Solving Approach