#include <iostream>
using namespace std;

class Figure{
protected:
 int w,h;
public:
 
 Figure(int wi,int he){
  w=wi;
  h=he;
 }
 virtual void Calulate()=0;
};
class Circle : public Figure{
 public:
  Circle(int radius):Figure(radius,0){}
  void Calulate(){
   cout<<"Circle : radius = "<<w<<"=>"<<w*w*3.14<<endl;
  }
};
class Square :public Figure{
public:
 Square(int width,int height): Figure(width,height){}
 void Calulate(){
  cout<<"Square : ("<<w<<", "<<h<<")=>"<<w*h<<endl;
 }
};
class Triangle:public Figure{
public:
 Triangle(int width,int height):Figure(width,height){}
 void Calulate(){
  cout<<"Triangle : ("<<w<<", "<<h<<")=>"<<w*h/2<<endl;
 }
};
int main(){
 Figure* fig[3]{new Circle(5),new Square(2,5),new Triangle(4,5)};
 for(int i=0;i<3;i++){
  fig[i]->Calulate();
 }
 return 0;
}

--------------------------------------------------------------

Figure클래스의 Calulate함수를 순수가상함수로 선언해 각 자식클래스에서 재정의하여 계산하도록 변경하였다.