Design Patterns discussion

["foxgem" <jianhgreat AT hotmail.com>]

> I have 2 clear and simple questions:
> 
> 1) The GOF book mentions in the Related Patterns section of Prototype
> pattern (p. 126) that "Design that make heavy use of the Composite and
> Decorator patterns often can benefit from Prototype as well".
> 
> My question is, how, exactly? Any simple C++ examples illustrating would
> be welcome.
> 
suppose u want to get a copy of a Composite, hope this code will be helpful 
to u.

class Component{
 public:
  virtual Component* Clone()=0;
     virtual ~Component();
  virtual void Add( Componet*)=0;
  virtual void Remove( Component*)=0;
  .............
};

class Composite: public Component
{
 public:
  ......
  inline void Add( Componet* co){
         m_Children.pushback( co);
     }
 private:
  vector< Composite*> m_Children;
};

Component* Composite::Clone(){
 vector< Composite*>::iterator it;
 Composite* co= new Composite();

 //Clone the Children
    for(it = m_Children.begin(); it != m_Children.end(); it++)
  co->Add( (*it)->Clone());

 //Assign some property of this object;

 return co; 
}

class Leaf: public Component
{
 ........
};

Component* Leaf::Clone(){
 Leaf* leaf= new Leaf();

 //Assign some property of this object;

 return leaf;
}