#include <iostream>
using namespace std;
 
class Shape {
public:
   virtual void virtualfunc()  { std::cout << "In shape\n"; }
};
 
class Circle: public Shape {
public:
   void virtualfunc()  { std::cout << "In Circle\n"; };
};
 
int main() {
   Circle circle_instance;
   
   // don't care what kind of Shape
   Shape &someShape = circle_instance;
 
   someShape.virtualfunc();
}