【設計模式】之二十一Factory Method

Type: Creational

Factory Method: 定義一個建立對象的介面，但是讓子類決定執行個體化那個類。新增加一個產品的時候，只需派生一個該類型的工廠而無需修改原來的代碼。每個具體工廠只負責返回一種產品類。是最典型的模板方法模式(Templete Method pattern)應用。

#include <iostream>using namespace std;class Product{};class ConcreteProduct: public Product{public:    ConcreteProduct()    {        cout<<"ConcreteProduct"<<endl;    };};class Creator{public:    virtual Product* factoryMethod() = 0;};class ConcreteCreator: public Creator{public:    Product* factoryMethod()    {        cout<<"ConcreteCreator decide which class to instantiate"<<endl;        return new ConcreteProduct;    };};int main(){    Creator* pCreator = new ConcreteCreator;    Product* pProduct = pCreator->factoryMethod();    system("pause");};