虚析构函数

#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;
}

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 A
16 {
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 }