Type: Behavioral

#include 
    
       using namespace std;  typedef int Request;  class Handler  {  public:      Handler(Handler *pSuccessor = NULL):m_pSuccessor(pSuccessor){};      // 纯虚函数,由派生类实现      virtual void handleRequest(Request request) = 0;  protected:      Handler* m_pSuccessor;  };  class ConcreateHandler1: public Handler  {  public:          void handleRequest(Request request)      {          if(request > 0)          {              cout<<"ConcreateHandler1 handle request."<
     
      handleRequest(request);              }          }      }  };  class ConcreateHandler2: public Handler  {  public:      ConcreateHandler2(Handler *pSuccessor = NULL){          m_pSuccessor = pSuccessor;      }      void handleRequest(Request request)      {          if(request > 10)          {              cout<<"ConcreateHandler2 handle request."<
      
       handleRequest(request);              }          }      }  };  int main()  {      Handler *p1 = new ConcreateHandler1();      Handler *p2 = new ConcreateHandler2(p1);      Request request = 1;      p2->handleRequest(request);      request = 12;      p2->handleRequest(request);      system("pause");      return 0;  }