装饰模式(Decorator)_c++

#include <string>
#include <iostream>
using namespace std;

class Component
{
public:
    virtual void Operation(){};
};

class ConcreateComponent :public Component
{
public:
    void Operation()
    {
        cout<<"具体对象的操作"<<endl;
    }
};

class Decorator : public Component
{
protected:
    Component* m_component;

public:
    Decorator()
    {
        m_component = NULL;
    }
    void SetCompenent(Component* component)
    {
        m_component = component;
    }

    virtual void Operation()
    {
        if (m_component != NULL)
        {
            m_component->Operation();
        }
    }
};

class ConcreateDecoratorA : public Decorator
{
private:
    //Decorator m_decorator;

    string addedState;

public:
    //ConcreateDecoratorA():

    void Operation()
    {
        Decorator::Operation();
        addedState = "New state";
        cout<<"具体装饰对象A的操作"<<endl;
    }
};


class ConcreateDecoratorB : public Decorator
{
private:
    //Decorator m_decorator;

    //string addedState;


public:
    //ConcreateDecoratorA():

    void Operation()
    {
        Decorator::Operation();
        cout<<"具体装饰对象B的操作"<<endl;
    }
};

int main(void)
{
    ConcreateComponent* c = new ConcreateComponent();
    ConcreateDecoratorA *da = new ConcreateDecoratorA();
    ConcreateDecoratorA *da2 = new ConcreateDecoratorA();
    ConcreateDecoratorB *db = new ConcreateDecoratorB();

    da->SetCompenent(c);
    db->SetCompenent(da);
    da2->SetCompenent(db);

    da2->Operation();
};