模式定义：

外观模式提供了一个统一的接口，用来访问子系统中的一群接口。外观定义了一个高层接口，让子系统更容易使用。

模式结构：

举例：

构造一个家庭影院，当启动watchMovie方法时可以看电影，当使用endMovie时关闭电影。

编程实现及执行结果：

#include 
  
   
using namespace std;
//
   组件类
class Amplifier
{
public:
	void on()
	{
		cout << "Amplifier on" << endl;
	}

	void off()
	{
		cout << "Amplifier off" << endl;
	}
};


class Tuner
{
public:
	void on()
	{
		cout << "Tuner on" << endl;
	}

	void off()
	{
		cout << "Tuner off" << endl;
	}
};

class DvdPlayer
{
public:
	void on()
	{
		cout << "DvdPlayer on" << endl;
	}

	void off()
	{
		cout << "DvdPlayer off" << endl;
	}
};

class Screen
{
public:
	void on()
	{
		cout << "Screen on" << endl;
	}

	void off()
	{
		cout << "Screen off" << endl;
	}
};
//家庭影院
class HomeTheaterFacade
{
public:
	//统一接口
	void watchMovie()
	{
		amp.on();
		tuner.on();
		dvd.on();
		screen.on();
	}

	void endMovie()
	{
		amp.off();
		tuner.off();
		dvd.off();
		screen.off();
	}
	
	HomeTheaterFacade(Amplifier am,
	Tuner tune,
	DvdPlayer dv,
	Screen scree)
	{
		amp = am;
		tuner = tune;
		dvd = dv;
		screen = scree;
	}
	//~HomeTheaterFacade(){}
private:
	Amplifier amp;
	Tuner tuner;
	DvdPlayer dvd;
	Screen screen;
};
//客户代码
int main()
{
	Amplifier amp;
	Tuner tuner;
	DvdPlayer dvd;
	Screen screen;

	HomeTheaterFacade homeTheaterFacade(amp,tuner,dvd,screen);;
	homeTheaterFacade.watchMovie();
	homeTheaterFacade.endMovie();
	return 0;
}
  

执行结果：

Amplifieron

Tuneron

DvdPlayeron

Screenon

Amplifieroff

Tuneroff

DvdPlayeroff

Screenoff

请按任意键继续. . .

设计原则：

最少知识原则：只和你的密友谈话