#include <iostream>#include <list>#include <string>using namespace std;class menu{public:  menu(string in) : name(in){}  ~menu(){}  virtual void Add(menu*) = 0;  virtual void Remove(menu*) = 0;  virtual void showname() = 0;protected:  string name;};class Leafmenu : public menu{public:  Leafmenu(string in) : menu(in){}  ~Leafmenu(){}  void showname()  {    cout<< "Leaf : " << name << endl;  }  virtual void Add(menu*){}  virtual void Remove(menu*){}};class Compositemenu : public menu{public:  Compositemenu(string in) : menu(in){}  void showname()  {    cout<< "Composit : "<< name << endl;    list<menu*>::iterator iter = m_child.begin();    while (iter != m_child.end())    {      (*iter)->showname();      iter++;    }  }  virtual void Add(menu*m){ m_child.push_back(m); }  virtual void Remove(menu*m){ m_child.remove(m); }private:  list<menu*> m_child;};//調用實現int main{  Compositemenu mainmenu("Main");  /***添加File菜單****/  Compositemenu *pFile = new Compositemenu("File");  Leafmenu *pNew = new Leafmenu("New");  Leafmenu *pOpen = new Leafmenu("Open");  Leafmenu *pClose = new Leafmenu("Close");  pFile->Add(pNew);  pFile->Add(pOpen);  pFile->Add(pClose);  mainmenu.Add(pFile);  /***添加Edit菜單****/  Compositemenu *pEdit = new Compositemenu("Edit");  Leafmenu *pCopy = new Leafmenu("Copy");  Leafmenu *pPaste = new Leafmenu("Paste");  pEdit->Add(pCopy);  pEdit->Add(pPaste);  mainmenu.Add(pFile);  Leafmenu *pExit = new Leafmenu("Exit");  Leafmenu *pHelp = new Leafmenu("Help");  mainmenu.Add(pExit);  mainmenu.Add(pHelp);  mainmenu.showname();  delete pNew;  delete pOpen;  delete pClose;  delete pFile;  delete pCopy;  delete pPaste;  delete pEdit;  delete pExit;  delete pHelp;}