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+//工厂方法，类工厂以及抽象工厂（和构造器模式有一些重叠）
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+//工厂的核心是对类的构建
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+#include<memory>
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+#include<iostream>
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+#include<map>
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+//从基本的类开始
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+//给一个类设计一个工厂方法
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+//工厂方法的好处是可以直接强制对外要求生成的类的封装格式（如智能指针，json数据流等）
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+class basic_factory
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+{
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+private:
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+ int data;
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+protected:
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+ basic_factory(){}
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+public:
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+ static std::shared_ptr<basic_factory> create() //一个简单的工厂方法，只能通过工厂方法构建(这样可以强制要求只能获取智能指针中的对象)
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+ {
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+ return std::shared_ptr<basic_factory>(new basic_factory);
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+ }
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+
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+};
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+
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+
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+//类工厂（简单版本）
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+//将所有类的的构造函数全部设置为protected，将工厂类设置为对应类的友元(即一种侵入式的构建方式，必须在设计的时候就做好，否则很难修改)
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+
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+class factory;
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+class A
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+{
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+ int data;
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+ friend factory;
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+protected:
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+ A(){}
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+};
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+
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+class B
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+{
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+ int data;
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+ friend factory;
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+protected:
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+ B(){}
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+};
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+
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+//当然由于只有工厂能创建对象（产品）那么实际上工厂还可以负责售后（因为工厂有所有的类的信息），即保存每一个数据指针，最后一次性释放空间
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+class factory
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+{
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+public:
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+ static std::shared_ptr<A> create_A()
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+ {
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+ return std::shared_ptr<A>(new A);
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+ }
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+ static std::shared_ptr<B> create_B()
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+ {
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+ return std::shared_ptr<B>(new B);
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+ }
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+};
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+
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+//工厂方法与多态
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+class base
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+{
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+public:
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+ virtual void print()
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+ {
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+ std::cout<<"basic"<<std::endl;
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+ }
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+};
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+
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+class base_A:public base
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+{
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+public:
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+ void print()override
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+ {
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+ std::cout<<"A"<<std::endl;
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+ }
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+};
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+class base_B:public base
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+{
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+public:
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+ void print()override
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+ {
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+ std::cout<<"B"<<std::endl;
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+ }
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+};
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+
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+class factory_V
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+{
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+public:
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+
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+ static std::shared_ptr<base> create(int type)
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+ {
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+ switch(type)
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+ {
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+ case 1:
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+ {
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+ return std::shared_ptr<base>(new base);
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+ break;
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+ }
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+ case 2:
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+ {
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+ return std::shared_ptr<base>(new base_A);
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+ break;
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+ }
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+ case 3:
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+ {
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+ return std::shared_ptr<base>(new base_B);
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+ break;
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+ }
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+ default:
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+ return std::shared_ptr<base>(new base);
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+ }
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+ }
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+};
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+
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+//嵌套工厂（在类内定义工厂）直接将类和工厂绑定
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+class insert
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+{
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+ int data;
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+ class factory
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+ {
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+ protected:
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+ factory()=default;
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+ public:
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+ std::shared_ptr<insert> create()
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+ {
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+ return std::move(std::shared_ptr<insert>(new insert));
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+ }
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+ };
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+public:
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+ static factory lab;
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+};
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+
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+//抽象工厂
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+//抽象工厂设计模式是一种高度复杂的设计模式
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+//抽象工厂的名称来源是当有大量相似的物体需要不同的工厂，会设计一个抽象类（抽象工厂作为接口），其余的工厂从这个抽象工厂中继承
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+//当然最后为了不使用这么大量的工厂，还会在使用一个工厂对所有的构造工厂进行封装
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+//总感觉带点过度设计的意思
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+
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+//有两种饮料，要分别准备
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+class prepare_coffee;
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+class prepare_water;
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+struct drink
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+{
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+
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+};
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+struct coffee:public drink
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+{
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+ int c;
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+private:
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+ coffee()=default;
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+ friend prepare_coffee;
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+};
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+struct water:public drink
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+{
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+ int c;
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+private:
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+ water()=default;
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+ friend prepare_water;
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+};
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+
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+class abstract //抽象工厂
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+{
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+public:
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+ virtual std::shared_ptr<drink> prepare()=0;
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+};
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+
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+class prepare_water:public abstract
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+{
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+public:
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+ std::shared_ptr<drink> prepare()override
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+ {
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+ return std::move(std::shared_ptr<drink>(new water));
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+ }
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+};
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+
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+class prepare_coffee:public abstract
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+{
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+public:
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+ std::shared_ptr<drink> prepare()override
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+ {
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+ return std::move(std::shared_ptr<drink>(new coffee));
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+ }
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+};
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+
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+//当然如果用工厂群太抽象了
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+class prepare_drink
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+{
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+private:
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+ std::map<std::string,std::shared_ptr<abstract>> prepare_drinks;
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+public:
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+ prepare_drink()
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+ {
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+ prepare_drinks["coffee"]=std::make_shared<prepare_coffee>();
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+ prepare_drinks["water"]=std::make_shared<prepare_water>();
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+ }
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+ std::shared_ptr<drink> prepare(const std::string& name)
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+ {
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+ std::shared_ptr<drink> result=prepare_drinks[name]->prepare();
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+ return std::move(result);
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+ }
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+};
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+
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+int main()
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+{
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+ basic_factory::create();
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+
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+ factory_V::create(1)->print();
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+ factory_V::create(2)->print();
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+ factory_V::create(3)->print();
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+
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+ insert::lab.create();
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+}
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