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
    uint16_t bit;
    int j = 0;
    while(reg) { 
        if(reg & (1 << 0)) {  
            bit |= (1 << j);
        }
        reg = reg >> 2; 
        j++;
    }
    return bit;
}

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

Solving Approach