C++设计模式之迭代器模式（Iterator）

class Item
{
public:
  Item(string strName,float price):
  m_name(strName),m_price(price){}
  Item(Item& item):
  m_name(item.strName),m_price(item.price){}
    string tostring()
  {
    std::ostringstream buffer;
    buffer << f;
    string strPrice = buffer.str();
    strName += " :";
        return strName + strPrice;
  }
private:
  string m_name;
  float m_price;
}

class Container；
class Menu；

class Iterator
{
public:
  virtual ~Iterator(){}
  virtual void first()=0;
  virtual void next()=0;
  virtual bool hasnext()=0;
  virtual Item* current()=0;
protected:
  Container * m_pContainer;
}


class Container 
{
public:
  virtual ~Container() {};
  virtual void CreateIterator()= 0; 
protected:
  Observer(){};
};

class MenuIterator : public Iterator
{ 
  Menu * m_menu; 
  int curpos; 
public: 
  MenuIterator(Menu*a):m_menu(a),curpos(0){} 
  virtual void first() 
  { 
    curpos=0; 
  } 
  virtual void next() 
  { 
    curpos++; 
  } 
  virtual bool hasnext() 
  { 
    if(curpos >=0 && curpos< m_menu->size()) 
  } 
  virtual Item* current() 
  {
    return m_menu->value(curpos); 
  }
}; 


class Menu : public Container
{
public:
  virtual ~Menu() 
  {
    for(int i=0 ; i< m_items.size(); i++)
    {
      delete m_items[i];
    }
  };
  Iterator* CreateIterator() 
  {
    return new MenuIterator(this); 
  }
    int size()
  {
    return m_items.size();
  }
  Item* value(int nIndex)
  {
    if(nIndex>=0 && nIndex<m_items.size())
    {
      return m_items[nIndex];
    }
    else
    {
      return NULL;
    }
  }
  void additem(Item& item)
  {
    Item *pItem = new Item(item);
    m_items.push_back(pItem);
  }
    
private: 
  vector<item* > m_items; 
};


int main()
{
  Item it1("chicken", 10.0);
    Item it2("Apple", 5.0);
    Item it3("Beaf", 20.0);
    Item it4("soup",15.0);
    
    Menu menu;
  menu.additem(it1);
  menu.additem(it2);
  menu.additem(it3);
  menu.additem(it4);
  
    Iterator itor = menu.CreateIterator();
  while(itor->hasnext())
  {
    Item* pItem = itor->current();
    if(pItem)
      cout<<pItem->tostring()<<endl;
    itor->next();
  }
}