工厂模式中使用了多态的原理，来将具体实现和接口进行有效的解耦合，符合开闭原则和依赖倒置原则
需要新加功能的时候不需要对原有代码进行修改。
抽象类human和抽象类factory就是调用接口，而实际的生产过程通过factory的子类(如boyfactory)来new
一个具体的human(如:boy)子类然后返回一个human父类的指针完成，如下图：

具体的代码如下：

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#include<iostream>
using namespace std;
//工厂模式新增功能并不会修改原有代码符合开闭原则
//使用多态实现
//纯虚拟接口
class human
{
public:
virtual void getman(void) = 0;
virtual ~human()
{
//cout<<"4:"<<endl;
}
};
class factory
{
public:
virtual human* greman(void) = 0;
virtual ~factory()
{
// cout<<"3:"<<endl;
}
};
/////boy
class boy:public human
{
public:
virtual void getman(void)
{
cout<<"I'M BOY!"<<endl;
}
virtual ~boy()
{
// cout<<"2:"<<endl;
}
};
class boyfactory:public factory
{
private:
boy* p;
public:
virtual human* greman(void) //负责生产boy言外之意就是调用一个new来new出内存空间
{
p = new boy;
return p;
}
virtual ~boyfactory()
{
// cout<<"1:"<<endl;
delete p;
}
};
//后来新建的woman工厂和woman定义
//////////////woman
class woman:public human
{
public:
virtual void getman(void)
{
cout<<"I'M woman!"<<endl;
}
virtual ~woman()
{
// cout<<"5:"<<endl;
}
};
class womanfactory:public factory
{
private:
woman* p;
public:
virtual human* greman(void) //负责生产woman言外之意就是调用一个new来new出内存空间
{
p = new woman;
return p;
}
virtual ~womanfactory()
{
//cout<<"6:"<<endl;
delete p;
}
};
///////////////////////
int main(void)
{
//生产boy
factory* fa1= new boyfactory;
human* hm1 = NULL;
hm1 = fa1->greman();
hm1->getman();
delete fa1;
//生产woman
factory* fa2= new womanfactory;
human* hm2 = NULL;
hm2 = fa2->greman();
hm2->getman();
delete fa2;
cout<<"hello!"<<endl;
}

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