C++ デザイン パターンの抽象ファクトリ パターンの簡単な紹介

[code]//create ProductA
class ProductA{
public:
    virtual void Show() = 0;
};

class ProductA1: public ProductA{
public:
    void Show(){
        std::cout << "I&#39;m ProductA1\n";
    }
};

class ProductA2: public ProductA{
public:
    void Show(){
        std::cout << "I&#39;m ProductA2\n";
    }
};

//create ProductB
class ProductB{
public:
    virtual void Show() = 0;
};

class ProductB1: public ProductB{
public:
    void Show(){
        std::cout << "I&#39;m ProductB1\n";
    }
};

class ProductB2: public ProductB{
public:
    void Show(){
        std::cout << "I&#39;m ProductB2\n";
    }
};

class Factory{
public:
    virtual ProductA *CreateProductA() = 0;
    virtual ProductB *CreateProductB() = 0;
};

class Factory1: public Factory{
public:
    ProductA *CreateProductA(){
        return new ProductA1();
    }

    ProductB *CreateProductB(){
        return new ProductB1();
    }
};

class Factory2: public Factory{
public:
    ProductA *CreateProductA(){
        return new ProductA2();
    }

    ProductB *CreateProductB(){
        return new ProductB2();
    }
};

template <typename T>
void del(T* obj){
    if( obj != NULL){
        delete obj;
        obj = NULL;
    }
}

[code]int main(){
    Factory *factoryObj1 = new Factory1();
    ProductA *productObjA1 = factoryObj1->CreateProductA();
    ProductB *productObjB1 = factoryObj1->CreateProductB();

    productObjA1->Show();  //Output： I'm ProductA1
    productObjB1->Show();  //Output： I'm ProductB1

    Factory *factoryObj2 = new Factory2();
    ProductA *productObjA2 = factoryObj2->CreateProductA();
    ProductB *productObjB2 = factoryObj2->CreateProductB();

    productObjA2->Show();  //Output：I'm ProductA2
    productObjB2->Show();  //Output：I'm ProductB2

    del(productObjB2);
    del(productObjA2);
    del(factoryObj2);
    del(productObjB1);
    del(productObjA1);
    del(factoryObj1);

    return 0;
}