工厂方法模式（Factory Method Pattern）

#ifndef FACTORYMETHOD_H
#define FACTORYMETHOD_H

#include<iostream>
using namespace std;

class Product//should be a pure virtual class.
{
public:
Product(){}
~Product(){}
};

class ConcreteProductA:public Product
{
public:
ConcreteProductA()
{
cout<<"ConcreteProductA is created."<<endl;
}
};

class ConcreteProductB:public Product
{
public:
ConcreteProductB()
{
cout<<"ConcreteProductB is created."<<endl;
}
};

class Creator
{
public:
virtual Product* createProduct()=0;
};

class ConcreteCreatorA:public Creator
{
public:
Product* createProduct()
{
return new ConcreteProductA();
}
};

class ConcreteCreatorB:public Creator
{
public:
Product* createProduct()
{
return new ConcreteProductB();
}
};

#endif//FACTORYMETHOD_H

int main()
{
Creator* creator=new ConcreteCreatorA();
creator->createProduct();
cout<<endl;

creator=new ConcreteCreatorB();
creator->createProduct();

return 0;
}