c++学习-多态性

#include<iostream>
#include<string>
#include <typeinfo>  
using namespace std;


class father{

public:
    void smart(){}
    virtual ~father(){}
};

class son : public father
{
public:
    void say()
    {
        cout << "say" << endl;
    }
};

void main()
{

    father *p;
    p= new son;
    dynamic_cast<son*>(p)->say();
    
}