22. Extract Even Bits Only from 32-bit Register

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

uint32_t extract_even_bits(uint32_t reg) {
    
    uint32_t ext_val = 0;
    
    for(int i=0 ; i<16 ; i++){
        ext_val |= ((reg >> 2*i) & 1U ) << i;
    }

    return ext_val;
}

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