#include <iostream>

#include <vector>

using namespace std;

#define DESTROY_POINTER(ptr) if (ptr) { delete ptr; ptr = NULL; }

class Element;

class Visitor

{

public:

    virtual void Visit(Element* pElement)=;

};

class ConcreteVisitorA : public Visitor

{

public:

    void Visit(Element* pElement);

};

class ConcreteVisitorB : public Visitor

{

public:

    void Visit(Element* pElement);

};

class Element

{

public:

    virtual void Accept(Visitor* pVisitor)=;

    virtual void Interface1()=;

    virtual void Interface2()=;

};

class ConcreteElementA : public Element

{

public:

    void Accept(Visitor* pVisitor)

    {

        pVisitor->Visit(this);

    }

    void Interface1() { cout<<"ConcreteElementA::Interface1"<<endl; }

    void Interface2() { cout<<"ConcreteElementA::Interface2"<<endl; }

};

class ConcreteElementB : public Element

{

public:

    void Accept(Visitor* pVisitor)

    {

        pVisitor->Visit(this);

    }

    void Interface1() { cout<<"ConcreteElementB::Interface1"<<endl; }

    void Interface2() { cout<<"ConcreteElementB::Interface2"<<endl; }

};

void ConcreteVisitorA::Visit(Element* pElement)

{

    pElement->Interface1();

}

void ConcreteVisitorB::Visit(Element* pElement)

{

    pElement->Interface2();

}

class Structure

{

public:

    virtual ~Structure()

    {

        for (unsigned int i = ; i < m_elementList.size(); i++)

        {

            delete m_elementList[i];

        }

        m_elementList.clear();

    }

    void Accept(Visitor* pVisitor)

    {

        for (unsigned int i = ; i < m_elementList.size(); i++)

        {

            m_elementList[i]->Accept(pVisitor);

        }

    }

    void AddElement(Element* pElement)

    {

        m_elementList.push_back(pElement);

    }

private:

    vector<Element*> m_elementList;

};

int main(int argc, char *argv[])

{

    Structure structure;

    structure.AddElement(new ConcreteElementA);

    structure.AddElement(new ConcreteElementB);

    Visitor* pVisitorA = new ConcreteVisitorA;

    Visitor* pVisitorB = new ConcreteVisitorB;

    structure.Accept(pVisitorA);

    structure.Accept(pVisitorB);

    DESTROY_POINTER(pVisitorA);

    DESTROY_POINTER(pVisitorB);

    return ;

}