commandpattern.cpp

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//: C10:CommandPattern.cpp
// From "Thinking in C++, Volume 2", by Bruce Eckel & Chuck Allison.
// (c) 1995-2004 MindView, Inc. All Rights Reserved.
// See source code use permissions stated in the file 'License.txt',
// distributed with the code package available at www.MindView.net.
#include <iostream>
#include <vector>
using namespace std;

class Command {
public:
  virtual void execute() = 0;
};

class Hello : public Command {
public:
  void execute() { cout << "Hello "; }
};

class World : public Command {
public:
  void execute() { cout << "World! "; }
};

class IAm : public Command {
public:
  void execute() { cout << "I'm the command pattern!"; }
};

// An object that holds commands:
class Macro {
  vector<Command*> commands;
public:
  void add(Command* c) { commands.push_back(c); }
  void run() {
    vector<Command*>::iterator it = commands.begin();
    while(it != commands.end())
      (*it++)->execute();
  }
};

int main() {
  Macro macro;
  macro.add(new Hello);
  macro.add(new World);
  macro.add(new IAm);
  macro.run();
} ///:~