简单工厂模式

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

protected:
private:
};


class Banana : public Fruit
{
public:
    virtual void getFruit()
    {
        cout<<"香蕉"<<endl;

    }
protected:
private:
};


class Pear : public Fruit
{
public:
    virtual void getFruit()
    {
        cout<<"梨子"<<endl;

    }
protected:
private:
};

class Factory 
{
public:
    static Fruit* Create(char *name)
    {
        Fruit *tmp = NULL;
        if (strcmp(name, "pear") == 0)
        {
            tmp = new Pear();
        }
        else if (strcmp(name, "banana") == 0)
        {
            tmp = new Banana();
        }
        else
        {
            return NULL;
        }
        return tmp;
    }
protected:
private:
};

void main()
{
    Fruit *pear =  Factory::Create("pear");
    if (pear == NULL)
    {
        cout<<"创建pear失败\n";
    }
    pear->getFruit();

    Fruit *banana =  Factory::Create("banana");
    banana->getFruit();

    system("pause");
}

工厂模式

简单工厂模式，当有新的对象需要创建时，需要修改factory类的方法，不符合开闭原则

工厂模式：当系统扩展需要添加新的产品对象时，仅仅需要添加一个具体对象以及一个具体工厂对象，原有工厂对象不需要

进行任何修改

#include "iostream"
using namespace std;

class Fruit
{
public:
    virtual void sayname()
    {
        cout<<"fruit\n";
    }
};

class FruitFactory
{
public:
    virtual Fruit* getFruit()
    {
        return new Fruit();
    }
};


//香蕉
class Banana : public Fruit
{
public:
    virtual void sayname()
    {
        cout<<"Banana \n"<<endl;
    }
};

//香蕉工厂
class BananaFactory : public  FruitFactory
{
public:
    virtual Fruit* getFruit()
    {
        return new Banana;
    }
};


//苹果
class Apple : public Fruit
{
public:
    virtual void sayname()
    {
        cout<<"Apple \n"<<endl;
    }
};

//苹果工厂
class AppleFactory : public  FruitFactory
{
public:
    virtual Fruit* getFruit()
    {
        return new Apple;
    }
};

void main()
{
    FruitFactory * ff  = NULL;
    Fruit *fruit = NULL;

    //1
    ff = new BananaFactory();
    fruit = ff->getFruit();
    fruit->sayname();

    delete fruit;
    delete ff;

    //2苹果
    ff = new AppleFactory();
    fruit = ff->getFruit();
    fruit->sayname();

    delete fruit;
    delete ff;

    cout<<"hello....\n";
    system("pause");
}

抽象工厂模式

工厂模式只能生产一个产品。（要么香蕉、要么苹果）

抽象工厂可以一下生产一个产品族（里面有很多产品组成）

class Fruit
{
public:
    virtual void sayname()
    {
        cout<<"fruit\n";
    }
};

class FruitFactory
{
public:
    virtual Fruit* getApple()
    {
        return new Fruit();
    }
    virtual Fruit* getBanana()
    {
        return new Fruit();
    }
};

//南方香蕉
class SouthBanana : public Fruit
{
public:
    virtual void sayname()
    {
        cout<<"South Banana \n"<<endl;
    }
};


//南方苹果
class SouthApple : public Fruit
{
public:
    virtual void sayname()
    {
        cout<<"South Apple \n"<<endl;
    }
};


//北方香蕉
class NorthBanana : public Fruit
{
public:
    virtual void sayname()
    {
        cout<<"North Banana \n"<<endl;
    }
};


//北方苹果
class NorthApple : public Fruit
{
public:
    virtual void sayname()
    {
        cout<<"North Apple \n"<<endl;
    }
};

class SourthFruitFactory : public FruitFactory
{
public:
    virtual Fruit* getApple()
    {
        return new SouthApple();
    }
    virtual Fruit* getBanana()
    {
        return new SouthBanana();
    }
};

class NorthFruitFactory : public FruitFactory
{
public:
    virtual Fruit* getApple()
    {
        return new NorthApple();
    }
    virtual Fruit* getBanana()
    {
        return new NorthBanana();
    }
};

void main()
{   
    FruitFactory * ff  = NULL;
    Fruit *fruit = NULL;

    ff = new SourthFruitFactory();
    fruit = ff->getApple();
    fruit->sayname();
    fruit = ff->getBanana();
    fruit->sayname();

    delete fruit;
    delete ff;

    ff = new NorthFruitFactory();
    fruit = ff->getApple();
    fruit->sayname();
    fruit = ff->getBanana();
    fruit->sayname();

    delete fruit;
    delete ff;

    cout<<"hello....\n";
    system("pause");
}