## 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 <iostream>
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
