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Decorator模式解决以下情况：我们需要为一个已经定义好的类添加新的职责（操作），通常的情况我们会定义一个新类继承自定义好的类，这样会带来一个问题。通过继承的方式解决这样的情况还带来了系统的复杂性，因为继承的深度会变得很深。而Decorator模式提供了一种给类增加职责的方法，不是通过继承实现，而是通过组合。

Decorator.h

//Decorator.h#ifndef _DECORATOR_H_#define _DECORATOR_H_class Component{public:	virtual ~Component();	virtual void Operation();protected:	Component();private:};class ConcreteComponent:public Component{public:	ConcreteComponent();	~ConcreteComponent();	void Operation();protected:private:};class Decorator:public Component{public:	Decorator(Component* com);	virtual ~Decorator();	void Operation();protected:	Component* _com;private:};class ConcreteDecorator:public Decorator{public:	ConcreteDecorator(Component* com);	~ConcreteDecorator();	void Operation();	void AddedBehavior();protected:private:};#endif //~_DECORATOR_H_

//Decorator.cpp#include "Decorator.h"#include 
   
    Component::Component(){}Component::~Component(){}void Component::Operation(){}ConcreteComponent::ConcreteComponent(){ }ConcreteComponent::~ConcreteComponent(){}void ConcreteComponent::Operation(){	std::cout<<"ConcreteComponent operation..."<
    
     _com = com;}Decorator::~Decorator(){	delete _com;}void Decorator::Operation(){}ConcreteDecorator::ConcreteDecorator(Component* com):Decorator(com){}ConcreteDecorator::~ConcreteDecorator(){}void ConcreteDecorator::AddedBehavior(){	std::cout<<"ConcreteDecorator::AddedBehacior...."<
     
      Operation();	this->AddedBehavior();}
     
    
   

#include "Decorator.h"#include 
   
    using namespace std;int main(){	Component* com = new ConcreteComponent();    Decorator* dec = new ConcreteDecorator(com);	dec->Operation();	delete dec;    return 0;}
   

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