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(C++)C++类继承中的构造函数和析构函数

C++继承 函数 构造函数 和析构
2023-09-14 09:00:36 时间

思想:

在C++的类继承中,

建立对象时,首先调用基类的构造函数,然后在调用下一个派生类的构造函数,依次类推;

析构对象时,其顺序正好与构造相反;

例子:

#include <iostream>
using namespace std;

class Shape{
public:
    void Draw() {cout<<"Base::Draw()"<<endl;}
    void Erase() {cout<<"Base::Erase()"<<endl;}
    Shape() {Draw();}
    ~Shape() {Erase();}
};
//-------------------------------------------------
class Polygon:public Shape{
public:
    Polygon() {Draw();}
    void Draw() {cout<<"Polygon::Draw()"<<endl;}
    void Erase() {cout<<"Polygon Erase()"<<endl;}
    ~Polygon() {Erase();}
};
//--------------------------------------------------
class Rectangle:public Polygon{
public:
    Rectangle() {Draw();}
    void Draw() {cout<<"Rectangle::Draw()"<<endl;}
    void Erase() {cout<<"Rectangle Erase()"<<endl;}
    ~Rectangle() {Erase();}
};
//--------------------------------------------------
class Square:public Rectangle{
public:
    Square() {Draw();}
    void Draw() {cout<<"Square::Draw()"<<endl;}
    void Erase() {cout<<"Square Erase()"<<endl;}
    ~Square() {Erase();}
};
//--------------------------------------------------
int main(){
    Polygon c;
    Rectangle s;
    Square t;
    cout<<"------------------------------------------"<<endl;
    return 0;
}

结果: