[Design Pattern] 抽象工厂模式

class Fruit
{
public:
    virtual void showName() = 0;
};

class Apple : public Fruit
{
public:
    virtual void showName()
    {
        cout << "I am apple." << endl;
    }
};
class Banana : public Fruit
{
public:
    virtual void showName()
    {
        cout << "I am banana." << endl;
    }
};
class Pear : public Fruit
{
public:
    virtual void showName()
    {
        cout << "I am pear." << endl;
    }
};

class FactoryMethod
{
public:
    virtual Fruit* createFruit() = 0;
};

class AppleFactory : public FactoryMethod
{
public:
    virtual Fruit* createFruit()
    {
        return new Apple();
    }
};
class BananaFactory : public FactoryMethod
{
public:
    virtual Fruit* createFruit()
    {
        return new Banana();
    }
};
class PearFactory : public FactoryMethod
{
public:
    virtual Fruit* createFruit()
    {
        return new Pear();
    }
};

int main()
{
    FactoryMethod* factory = new AppleFactory();
    Fruit* apple = factory->createFruit();
    apple->showName();
    delete factory;
    delete apple;
    return 0;
}