基类指针转子类

 #include<iostream>

    
 #include<typeinfo>
    
 using namespace std;
    
  
    
 class base
    
 {
    
    public:
    
     virtual void virtual_fun()
    
     {cout<<"base"<<endl;}
    
    
    
     void normal_fun()
    
     {cout<<"base"<<endl;}
    
 };
    
  
    
 class derived
    
 {
    
    public:
    
     virtual void virtual_fun()
    
     {cout<<"derived"<<endl;}
    
  
    
     void normal_fun()
    
     {cout<<"derived"<<endl;} 
    
  
    
 };
    
  
    
  
    
 int main()
    
 {
    
     base *cp=(base *)new derived;
    
     cp->virtual_fun();