设计模式——代理模式（C++实现）

 #include <iostream>
 #include <string>

 using namespace std;

 class CSubject
 {
 public:
         virtual void Request() = ;
 };

 class CRealSubject: public CSubject
 {
 public:
         virtual void Request()
         {
                 cout<< "ReadSubject request....."<< endl;
         }

 };

 class CProxy: public CSubject
 {
 public:
         CProxy()
         {
                 m_pstRealSubject = new CRealSubject();
         }

         virtual void Request()
         {
                 if (m_pstRealSubject == NULL)
                         m_pstRealSubject = new CRealSubject();

                 cout<< "CProxy Request...."<< endl;
                 m_pstRealSubject->Request();
         }

 private:
         CRealSubject* m_pstRealSubject;
 };

 int main(int argc, char* argv[])
 {
         CProxy* pstProxy = new CProxy();
         pstProxy->Request();

         return ;
 }
 /////////////////////////////////////
 [root@ ~/learn_code/design_pattern/5_proxy]$ ./proxy
 CProxy Request....
 ReadSubject request.....

参考：http://design-patterns.readthedocs.io/zh_CN/latest/structural_patterns/proxy.html