C++(21)-简单工厂模式

//1.一个基类 AbstractFruit
class AbstractFruit
{
    public:
      virtual void showName()=0; 
};
//2.3个水果类,派生类Apple ，pear，banana
class Apple:public AbstractFruit
{
    public:
      virtual void showName()
      {cout<<"我是苹果"<<endl;}    
};
class pear:public AbstractFruit
{
    public:
      virtual void showName()
      {cout<<"我是梨子"<<endl;}    
};
class banana:public AbstractFruit
{
    public:
      virtual void showName()
      {cout<<"我是香蕉"<<endl;}    
};

//3.一个工厂类
class FruitFactory{
    public:
        static AbstractFruit* CreateFruit(string flag){
            if(flag=="apple"){
                return new Apple;
            }
            else if(flag=="banana")
            {
                return new Banana;
            }
            else if(flag=="pear")
            {
                return new Pear;
            }
            else{
                return NULL;
            }
        }
    
};
//4.调用
void test01(){
    FruitFactory *factory=new FruitFactory;
    AbstractFruit *fruit=factory->CreateFruit("apple");
    fruit->ShowName();
    delete fruit;
    
    fruit=factory->CreateFruit("pear");
    fruit->ShowName();
    delete fruit;
    
    fruit=factory->CreateFruit("banana");
    fruit->ShowName();
    delete fruit;
    
    delete factory;
}

int main(void)
{
    test01();
    return 0;
}