/* proxy.cpp
 *
 * Example of Proxy Pattern.
 */

#include <iostream>

class Subject {

public:
  virtual void operation() = 0;
};

class RealSubject: public Subject {

public:
  virtual void operation() {
    std::cout << "RealSubject operation\n";
  }
};

class Proxy: public Subject {

public:
  virtual void operation() {

    std::cout << "Proxy operation\n"; 

    _real_subject.operation();
  }

private:
  RealSubject _real_subject;
};

class Client {

public:
  Client(Subject& subject) : _subject(subject) {}

  virtual void do_something() {
    
    _subject.operation();
  }

private:
  Subject& _subject;
};

int main() {
  Proxy proxy;

  Client client(proxy);

  client.do_something();
}