设计模式-工厂模式

工厂模式通常又可以分为简单工厂模式、工厂模式、抽象工厂模式；他们有一个共同的类并从它继承而来。

工厂的实现：

工厂（creater）角色

所有的内部逻辑可以被外部对象调用；

抽象(Product)角色

所有具体产品的公共接口；

具体产品（Concrete Product）

具体实例对象；

简单工厂模式代码实现：

#include<iostream>

using namespace std;

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

class Apple:public Fruit
{
public:
	virtual void GetFruit()
	{
		cout << "i am Apple" << endl;
	}
};

class Banana :public Fruit
{
public:
	virtual void GetFruit()
	{
		cout << "i am Banana" << endl;
	}
};

class Facotry
{
public:
	Fruit* SetFruit(const char* p)
	{
		if (strcmp(p, "Apple") == 0)
		{
			return new Apple;
		}
		else if (strcmp(p, "Banana") == 0)
		{
			return new Banana;
		}
		else
		{
			return nullptr;
		}
	}
};

int main()
{
	Facotry* f = new Facotry;
	Fruit* Banana = f->SetFruit("Banana");
	Banana->GetFruit();
	delete Banana;

	delete f;


	return system("pause");
}

工厂模式代码实现：

#include<iostream>

using namespace std;

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

class Apple:public Fruit
{
public:
	virtual void GetFruit()
	{
		cout << "i am Apple" << endl;
	}
};

class Pear :public Fruit
{
public:
	virtual void GetFruit()
	{
		cout << "i am Pear" << endl;
	}
};

class AdvFactory
{
public:
	virtual Fruit* SetFruit() = 0;
};


class AppleFactory :public AdvFactory
{
public:
	virtual Fruit* SetFruit()
	{
		return new Apple;
	}
};

class PearFactory :public AdvFactory
{
public:
	virtual Fruit* SetFruit()
	{
		return new Pear;
	}
};

int main()
{
	AdvFactory* Adv = nullptr;
	Fruit* f = nullptr;

	Adv = new AppleFactory;
	f = Adv->SetFruit();
	f->GetFruit();

	delete f;
	delete Adv;


	Adv = new PearFactory;
	f = Adv->SetFruit();
	f->GetFruit();

	delete f;
	delete Adv;

	return system("pause");
}

工厂模式与简单工厂模式的差异在于工厂模式的解耦和，实现功能的单一职责原则。