Effective C++ NVI手法

最新推荐文章于 2024-11-18 22:28:02 发布

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最新推荐文章于 2024-11-18 22:28:02 发布

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分类专栏： Effective C++

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关于NVI手法

#include <iostream>
using namespace std;
enum ShapeColor{Red,Green,Blue};
class Shape
{
public:

    void draw(ShapeColor color=Red)const
    {
    doDraw(color);
    }
private:
    virtual void doDraw(ShapeColor color) const=0;
};

class Rectangle:public Shape
{
public:

private:
    virtual void doDraw(ShapeColor color) const;
};

void Rectangle::doDraw(ShapeColor color) const
{
    cout<<"Rectangle's doDraw"<<"color= "<<color<<endl;
}

int main()
{
    Shape*p=new Rectangle;

    p->draw();

    return 0;
}

#include <iostream>
using namespace std;
enum ShapeColor{Red,Green,Blue};
class Shape
{
public:

    void draw(ShapeColor color=Red)const
    {
    doDraw(color);
    }
private:
    virtual void doDraw(ShapeColor color) const
    {
        cout<<"Shape's doDraw"<<"color= "<<color<<endl;
    }
};

class Rectangle:public Shape
{
public:

private:
    virtual void doDraw(ShapeColor color) const;
};

void Rectangle::doDraw(ShapeColor color) const
{
    cout<<"Rectangle's doDraw"<<"color= "<<color<<endl;
}

int main()
{
    Shape*p=new Shape;
    p->draw();
    delete p;
    p=NULL;
    Shape*q=new Rectangle;
    q->draw();
    delete q;
    q=NULL;

    return 0;
}

#include <iostream>
using namespace std;
enum ShapeColor{Red,Green,Blue};
class Shape
{
public:

    void draw(ShapeColor color=Red)const
    {
    doDraw(color);
    }
private:
     void doDraw(ShapeColor color) const
    {
        cout<<"Shape's doDraw"<<"color= "<<color<<endl;
    }
};

class Rectangle:public Shape
{
public:

private:
    void doDraw(ShapeColor color) const;
};

void Rectangle::doDraw(ShapeColor color) const
{
    cout<<"Rectangle's doDraw"<<"color= "<<color<<endl;
}

int main()
{
    Shape*p=new Shape;
    p->draw();
    delete p;
    p=NULL;
    Shape*q=new Rectangle;
    q->draw();
    delete q;
    q=NULL;

    return 0;
}