虚析构和纯虚析构

 1 #include<bits/stdc++.h>
 2 #include<iostream>
 3 using namespace std;
 4 
 5 class Animal
 6 {
 7 public:
 8     Animal()
 9     {
10         cout << "Animal构造函数调用" << endl;
11     }
12     virtual void speak() = 0;
13 
14     virtual~Animal() = 0;
15 };
16 
17 Animal::~Animal()
18 {
19     cout << "Animal 纯虚析构函数调用" << endl;
20 }
21 
22 class Cat:public Animal
23 {
24 public:
25     Cat(string name)
26     {
27         cout << "Cat 构造函数调用" << endl;
28         m_Name = new string(name);
29     }
30 
31     virtual void speak()
32     {
33         cout << *m_Name << "猫在说活" << endl;
34     }
35 
36     ~Cat()
37     {
38         cout << "猫析构函数调用" << endl;
39         if(this->m_Name != NULL)
40         {
41             delete m_Name;
42             m_Name = NULL;
43         }
44 
45     }
46 public:
47     string *m_Name;
48 };
49 
50 void test()
51 {
52     Animal *animal = new Cat("Tom");
53     animal->speak();
54     //通过父类指针去释放，会导致子类对象清理不干净，造成内存泄露
55     //解决方法是给父类增加虚析构函数
56     //虚析构函数是用来解决通过父类指针释放子类对象
57     delete animal;
58 }
59 
60 int main()
61 {
62     test();
63     return 0;
64 }