make a class Foo that has four Bar member variables, they all allocate memory using RAII and rule of five

class Bar
{
  public:
   Bar() = default;
   Bar(const Bar&) = default;
   Bar(Bar&&) = default;
   Bar& operator= (const Bar&) = default;
   Bar& operator= (Bar&&) = default;
   ~Bar() = default;
}

class Foo
{
  public:
   Foo() = default;
   Foo(const Foo&) = default;
   Foo(Foo&&) = default;
   Foo& operator= (const Foo&) = default;
   Foo& operator= (Foo&&) = default;
   ~Foo() = default;

  private:
   Bar bar1;
   Bar bar2;
   Bar bar3;
   Bar bar4;
}