虚析构函数

来源：互联网发布：电视定时开关机软件编辑：程序博客网时间：2024/05/17 01:44

#include <iostream>  using namespace std;class A{public:    A() { cout << "构造A!" << endl; };    virtual ~A() { cout << "析构A!" << endl; };    virtual void DoSomething() { cout << "A的DoSomething!" << endl; };};class B : public A{public:    B() { cout << "构造B!" << endl; };    ~B() { cout << "析构B!" << endl; };    void DoSomething() { cout << "B的DoSomething!" << endl; };};int main(){    A *Test1 = new A;    cout << "**************" << endl;    Test1->DoSomething();    cout << "**************" << endl;    delete Test1;    cout << "**************" << endl;    B *Test2 = new B;    cout << "**************" << endl;    Test2->DoSomething();    cout << "**************" << endl;    delete Test2;    cout << "**************" << endl;    A *Test3 = new B;    cout << "**************" << endl;    Test3->DoSomething();    cout << "**************" << endl;    delete Test3;    return 0;}

运行结果：

修改代码，删除virtual

1 #include <iostream>   2  3  4 using namespace std; 5  6 class A 7 { 8 public: 9     A() { cout << "构造A!" << endl; };10      ~A() { cout << "析构A!" << endl; };11 12     virtual void DoSomething() { cout << "A的DoSomething!" << endl; };13 };14 15 class B : public A16 {17 public:18     B() { cout << "构造B!" << endl; };19     ~B() { cout << "析构B!" << endl; };20 21     void DoSomething() { cout << "B的DoSomething!" << endl; };22 };23 24 int main()25 {26     A *Test1 = new A;27     cout << "**************" << endl;28     Test1->DoSomething();29     cout << "**************" << endl;30     delete Test1;31     cout << "**************" << endl;32     B *Test2 = new B;33     cout << "**************" << endl;34     Test2->DoSomething();35     cout << "**************" << endl;36     delete Test2;37     cout << "**************" << endl;38     A *Test3 = new B;39     cout << "**************" << endl;40     Test3->DoSomething();41     cout << "**************" << endl;42     delete Test3;43     return 0;44 }

运行结果：

如果是： B b；
修改代码
运行结果：

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