（五）工厂方法模式

GOOD：修正了简单工厂模式中不遵守开放－封闭原则。工厂方法模式把选择判断移到了客户端去实现，如果想添加新功能就不用修改原来的类，直接修改客户端即可。

#include <string>

#include <iostream>

using namespace std;

//实例基类，相当于Product(为了方便，没用抽象)

class LeiFeng

{

public:
virtual void Sweep()
{
cout << "雷锋扫地" << endl;
}

};

//学雷锋的大学生，相当于ConcreteProduct

class Student : public LeiFeng

{

public:
virtual void Sweep()
{
cout << "大学生扫地" << endl;
}

};

//学雷锋的志愿者，相当于ConcreteProduct

class Volenter : public LeiFeng

{

public:
virtual void Sweep()
{
cout << "志愿者扫地" << endl;
}

};

//工场基类Creator

class LeiFengFactory

{

public:
virtual LeiFeng* CreateLeiFeng()
{
return new LeiFeng();
}

};

//工场具体类

class StudentFactory : public LeiFengFactory

{

public:
virtual LeiFeng* CreateLeiFeng()
{
return new Student();
}

};

class VolenterFactory : public LeiFengFactory

{

public:
virtual LeiFeng* CreateLeiFeng()
{
return new Volenter();
}

};

//客户端

int main()

{

LeiFengFactory *lf = new LeiFengFactory();  // 父类指针;
LeiFeng *l = lf->CreateLeiFeng(); // 父类指针;
l->Sweep();

lf = new StudentFactory(); //父类指针指向子类对象；
l = lf->CreateLeiFeng();//父类指针指向子类对象；
l->Sweep();

lf = new VolenterFactory();//父类指针指向子类对象；
l = lf->CreateLeiFeng();//父类指针指向子类对象；
l->Sweep();

delete l;
delete lf;
return 0;

}