#include <iostream>
#include <bitset>

union U
{
  unsigned int i;
  struct
  {
    unsigned char _1;
    unsigned char _2;
    unsigned char _3;
    unsigned char _4;
  } byte;
};

int main()
{
  union U u;
  u.i = 0b00001000'00001001'00001011'00001111;
  std::cout << std::bitset<8>(u.byte._1) << std::endl
            << std::bitset<8>(u.byte._2) << std::endl
            << std::bitset<8>(u.byte._3) << std::endl
            << std::bitset<8>(u.byte._4) << std::endl;
}