===== Reference =====

  * design pattern matrix 
  * http://www.netobjectives.com/download/dpmatrix.pdf
  * http://uml.org.cn/sjms/pdf/dpmatrix.pdf
  * http://sourcemaking.com/design_patterns# CPlusPlus
  * [[Livre]] : http://rzr.online.fr/isbn/2841773507 # Design patterns Tête la première (Broché) fr
  * https://github.com/jwasham/coding-interview-university#dont-feel-you-arent-smart-enough# LearN
  * https://www.fluentcpp.com/2020/12/18/on-design-patterns-in-cpp/#


===== TEMPLATES =====

  // file:///~/singleton.hpp
  template <class T>
  class Singleton
  {
  public:
  static T* get() {
    if ( instance == 0 ) instance = new T;
    return instance;
  }
  protected:
  Singleton() { }
  ~Singleton() {  }
  private:
  static T* instance;
  };

  template<class T>
  T* Singleton<T>::instance = NULL; // here the tricky part

  // file:///~/main.cpp
  #include <string>
  using namespace std;
  #include "singleton.hpp"

  int main()
  {
  Singleton<string>::get();
  return EXIT_SUCCESS;
  }


Note: [[Microsoft]] msvs allows default types , not GCC so avoid those :
  template<class T = char> //...


===== TEMPLATES & DESIGN PATTERN =====

what do u think of this weird code :

  /// Design Pattern (with templates)
  template <class T>
  class VisitorAble {
  public:
   virtual int visit(T & in_data)=0;
  };

  template <class T>
  class AcceptAble {
  public:
   virtual int accept(T & in_visitor) { in_visitor.visit( *this ); }
  };

  class Visitor : public Visitor<Data> { public: ... visit ... };

  class Data : public AcceptAble<VisitorAble<Data> >  {};

  // recursive template ?


===== MORE =====

@TaG: [[Design]] [[Pattern]] [[C++]] [[CPlusPlus]] [[templates]] [[DP]] [[pointers]] [[OOP]] [[STL]] [[auto_ptr]] [[boost]]