C++ML example 1

1.hh

#ifndef _1_H_
#define _1_H_

#include <iostream>

template <class TChild>
class GrandParent
{
protected:
  GrandParent() { }
  ~GrandParent() { }
private:
  void  Print_()
  {
    std::cout << "START Print (Parent)" << std::endl;
    static_cast<TChild*>(this)->Print_();
    std::cout << "End Print (Parent)" << std::endl;
  }
public:
  void  Print()
  {
    Print_();
  }
};

template <class TChild>
class Parent : public GrandParent<Parent<TChild> >
{
private:
  friend class GrandParent<Parent<TChild> >;
  void  Print_()
  {
    std::cout << "START Print (" << childName_ << ")" << std::endl;
    static_cast<TChild*>(this)->Print_();
    std::cout << "END Print (" << childName_ << ")" << std::endl;
  }
protected:
  Parent() { }
  ~Parent() { }
  std::string   childName_ = "<NONE>";
public:
  void  Print()
  {
    GrandParent<Parent<TChild> >::Print();
  }
};

class Child : public Parent<Child>
{
private:
  friend class Parent<Child>;
  void  Print_()
  {
    std::cout << "Child" << std::endl;
  }
public:
  Child()
  {
    Parent<Child>::childName_ = "Child";
  }
  ~Child() { }
  void  Print()
  {
    Parent<Child>::Print();
  }
};

#endif /* _1_H_ */

main1.cc

#include "1.hh"

int main(int argc, char *argv[])
{
  Child a;
  a.Print();
  return 0;
}