C++ 抽象类

一、整体代码

     01.cpp

#include <string>using namespace std;class Shape{public:    virtual void Draw() = 0;//纯虚函数    virtual ~Shape() {}//有向上转型，一般都申明成virtual};class Circle : public Shape{public:    void Draw()    {        cout<<"Circle::Draw() ..."<<endl;    }    ~Circle()    {        cout<<"~Circle ..."<<endl;    }};class Square : public Shape{public:    void Draw()    {        cout<<"Square::Draw() ..."<<endl;    }    ~Square()    {        cout<<"~Square ..."<<endl;    }};int main(){        Shape* shape = new Circle;        shape->Draw();}

二、解释

       纯虚函数用于该方法在不同的子类中实现不一样

       申明了纯虚函数，那么该类为抽象类，不能生成对象