派生类中的构造函数和析构函数

 1 class base_class{
 2 public:
 3     base_class(){
 4     cout<<"base_class constructor called\n";
 5     }
 6     ~base_class(){cout<<"base_class destructor called\n";  //虚函数  将调用派生类的析构函数 再调用基类的析构函数
 7 }
 8 };
 9 class derived_class:public base_class{
10 public:
11     derived_class(){
12     cout<<"derived_class constructor called\n";
13     }
14     ~derived_class(){
15     cout<<"derived_class destructor called\n";    
16     }
17 };
18 void main(){
19     derived_class *sample_ptr=new derived_class;  //当创建一个派生类变量时，先调用基类的构造函数，再调用派生类的构造函数
20     system("pause"); 
21 }

1 void main(){
2     derived_class *sample_ptr=new derived_class;  //当创建一个派生类变量时，先调用基类的构造函数，再调用派生类的构造函数
3     delete sample_ptr; 
4     sample_ptr=NULL;        //删除变量后，调用析构函数，首先调用派生类的析构函数，然后调用基类的析构函数
5     system("pause"); 
6 }