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
    uint16_t m;
    int j=0;
    for(int i=0;i<=30;i=i+2){
        while(j<16)
            if(reg&(1<<i)){
                m |=(1<<j);
                j++;
                break;
            }
            else{
                m &=~(1<<j);
                j++;
                break;
            }

        }

    return m;
}

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

Solving Approach