Empty member private inheritance

#include <cstdio>

namespace {
  class Empty
  {
  public:
    void do_something()
    {}
  };
  class NonEmpty
  {
    int foo;
  public:
    void do_something()
    {}
  };

  template<class T>
  class EmptyMember
  {
    T member;
    int foo;
  public:
    EmptyMember(const T& member):
      member(member)
    {
      this->member.do_something();
    }
  };
  template<class T>
  class EmptyBase: private T
  {
    int foo;
  public:
    EmptyBase(const T& base):
      T(base)
    {
      this->do_something();
    }
  };
  template<class T>
  EmptyMember<T> member_wrapper(const T& member)
  {
    return EmptyMember<T>(member);
  }
  template<class T>
  EmptyBase<T> class_wrapper(const T& member)
  {
    return EmptyBase<T>(member);
  }
  template<class T>
  size_t get_size(const T& obj)
  {
    return sizeof(obj);
  }
}

int main()
{
  Empty e;
  NonEmpty n;
  std::printf("Empty member: %zd; empty base: %zd\n",
          get_size(member_wrapper(e)),
          get_size(class_wrapper(e)));
  std::printf("Non-empty member: %zd; non-empty base: %zd\n",
          get_size(member_wrapper(n)),
          get_size(class_wrapper(n)));

  return 0;
}