工厂方法模式

工厂方法模式 定义了一个创建对象的接口，但由子类决定要实例化的类是哪一个。工厂方法让类把实例化推迟到子类。

#include <iostream>
#include <string>


using namespace std;


struct AbstractProduct {
    virtual void operation() = 0;
};

struct ProductA : public AbstractProduct {
    void operation() {
        cout << "ProductA" << endl;
    }
};

struct ProductB : public AbstractProduct {
    void operation() {
        cout << "ProductB" << endl;
    }
};


struct AbstractFactory {
    virtual AbstractProduct *createProduct() = 0;
};

struct FactoryA : public AbstractFactory {
    AbstractProduct *createProduct() {
        return new ProductA();
    }
};

struct FactoryB : public AbstractFactory {
    AbstractProduct *createProduct() {
        return new ProductB();
    }
};


int main(int argc, char **argv)
{
    AbstractFactory *factoryA = new FactoryA();
    AbstractProduct *p1 = factoryA->createProduct();
    p1->operation();
    delete p1;
    delete factoryA;

    AbstractFactory *factoryB = new FactoryB();
    AbstractProduct *p2 = factoryB->createProduct();
    p2->operation();
    delete p2;
    delete factoryB;

    return 0;
}