设计模式-行为-访问者

#pragma once

#ifndef VISITOR_H 

#define VISITOR_H 

class Visitor; 

class Element 
{ 
public: 
	virtual ~Element(){} 
	virtual void Accept(Visitor &rVisitor) = 0; 
protected: 
	Element(){} 
}; 

class ConcreateElementA : public Element 
{ 
public: 
	virtual ~ConcreateElementA() {} 
	virtual void Accept(Visitor &rVisitor); 
}; 

class ConcreateElementB : public Element 
{ 
public: 
	virtual ~ConcreateElementB() {} 
	virtual void Accept(Visitor &rVisitor); 
}; 

class Visitor 
{ 
public: 
	virtual ~Visitor(){} 
	virtual void VisitConcreateElementA(ConcreateElementA *pConcreateElementA) = 0; 
	virtual void VisitConcreateElementB(ConcreateElementB *pConcreateElementB) = 0; 

protected: 
	Visitor(){} 
}; 

class ConcreateVisitorA : public Visitor 
{ 
public: 
	virtual ~ConcreateVisitorA(){} 
	virtual void VisitConcreateElementA(ConcreateElementA *pConcreateElementA); 
	virtual void VisitConcreateElementB(ConcreateElementB *pConcreateElementB); 
}; 

class ConcreateVisitorB : public Visitor 
{ 
public: 
	virtual ~ConcreateVisitorB(){}
	virtual void VisitConcreateElementA(ConcreateElementA *pConcreateElementA); 
	virtual void VisitConcreateElementB(ConcreateElementB *pConcreateElementB); 
}; 

#endif 

#include "StdAfx.h"
#include "visitor_impl.h"

#include  

void ConcreateElementA::Accept(Visitor &rVisitor) 
{ 
	rVisitor.VisitConcreateElementA(this); 
} 

void ConcreateElementB::Accept(Visitor &rVisitor) 
{ 
	rVisitor.VisitConcreateElementB(this); 
} 

void ConcreateVisitorA::VisitConcreateElementA(ConcreateElementA *pConcreateElementA)
{ 
	std::cout Accept(*pVisitor2); 

	delete pElementA; 
	delete pElementB; 
	delete pVisitor1;
	delete pVisitor2;

	system("pause");

	return 0;
}