【Design Pattern】外观模式 Facade

外观模式

外观模式其实很简单，就是把一系列的方法进行封装。比如说以下这个游戏有两个怪物，一个是小怪一个是boss。当游戏难度的不同时怪物的血量会不同。请看如下代码：

class Monster
{
private:
int HP;
public:
Monster(int HP)
{
this->HP = HP;
}
};

class Small_monster:public Monster
{

public:
Small_monster(int HP):Monster(HP)
{
}
};

class Boss_monster:public Monster
{

public:
Boss_monster(int HP):Monster(HP)
{
}
};

那么在客户端要使用的话会这样做：
class Client
{
public:
static client_func()
{
//easy level
vector<Monster*> easy_level;
Monster* small = new Small_monster(200);
Monster* boss = new Boss_monster(2000);
easy_level.push_back(small);
easy_level.push_back(boss);

//middle level
vector<Monster*> middle_level;
Monster* small = new Small_monster(2000);
Monster* boss = new Boss_monster(20000);
easy_level.push_back(small);
easy_level.push_back(boss);

//hard level
vector<Monster*> hard_level;
Monster* small = new Small_monster(20000);
Monster* boss = new Boss_monster(200000);
easy_level.push_back(small);
easy_level.push_back(boss);
}
};

通过上述代码可以看到，

为了