代理模式&&装饰模式

一.代理模式 

class Subject
{
public:
	virtual void sailbook() = 0;
};
class RealSubjectBook {
public:
	virtual void sailbook() {
		cout << "实体店卖书" << endl;
	}
};
class dangdang :public Subject
{
public:
	virtual void sailbook() {
		RealSubjectBook *rsb = new RealSubjectBook;
		discount();
		rsb->sailbook();
		//cout << "网店卖书" << endl;
	}
	void discount() {
		cout << "打折" << endl;
	}
private:
	Subject *m_subject;
};
void main()
{
	Subject *s = new dangdang;
	s->sailbook();
	delete s;

	system("pause");
}

代理模式本质上是A中包含一个B类，A和B实现一个协议；这个设计模式理解起来很简单

二.装饰模式

对一个类进行功能性增强：

1.可以直接更改该类的代码；

2.可以通过新建一个类继承该类，再对新建的类进行功能增强；

3.可以通过组合的方式，就是新建一个类，该类里面包含要修改类的对象（装饰模式就是对该方法的增强）。

装饰者模式动态的给一个对象增加额外的职责，就增加功能来说，此模式更加灵活。

class Car {
public:
	virtual void show() = 0;
};
class Runcar :public Car
{
	virtual void show()
	{
		cout << "车可以跑" << endl;
	}
};
class SwimCardecrator:public Car {
private:
	Car *m_car;
public:
	SwimCardecrator(Car *car)
	{
		this->m_car = car;
	}
	virtual void show()
	{
		m_car->show();
		cout << "车可以游" << endl;
	}
};
class FlyCardecrator :public Car {
private:
	Car *m_car;
public:
	FlyCardecrator(Car *car)
	{
		this->m_car = car;
	}
	virtual void show()
	{
		m_car->show();
		cout << "车可以飞" << endl;
	}
};
void main()
{
	Car *runcar = new Runcar;
	runcar->show();

	SwimCardecrator *addswimcar = new SwimCardecrator(runcar);

	FlyCardecrator *addflycar = new FlyCardecrator(addswimcar);

	addflycar->show();

	delete addflycar;
	delete addswimcar;
	delete runcar;

	system("pause");
}