小编use*_*784的帖子

假设我们有一个来自抽象基类的派生类.指向抽象基类的指针在main中声明,并通过"new"分配给派生类.如何从指向基类的指针(而不是派生类的对象)访问派生类的成员函数？

例:

#include <iostream>
using namespace std;

class clsStudent
{
public:
   virtual void display() = 0;// {cout<<"Student\n";}
};

class clsInternational : public clsStudent
{
public:
   void display(){cout<<"International\n";} 
   void passportNo(){cout<<"Pass\n";}
};

class local : public clsStudent
{
public:
   void display(){cout<<"International\n";}
   void icNo(){cout<<"IC\n";}
};


int main()
{
   clsStudent * s = new clsInternational;
   clsStudent * s2 = new local;

   s->display(); 
   s->passportNo();  //This won't work

   return 0;
}