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;
}