классы , площадь фигур

#include <iostream>

using namespace std;
class shaid{
public:
    virtual void print()=0;

 };

 class trriangle : public shaid{
 public:
    int a;
    int h;
    void print(){
        int S= (a*h)*0.5;
        cout <<  S << endl;
    }
 };
 class rectangl : public shaid{
 public:
    int a;
    int b;
    void print(){
        int S= a*b;
        cout <<  S << endl;
    }
 };
 class circle  : public shaid{
 public:
    int r;
    int pi;
    void print(){
        int S= pi*(r*r*r);
        cout <<  S << endl;
    }
 };

int main()
{
/*
   triangl d = dog();
   restangle c = cat();
   d.print();
   c.print();

   dog*a     = new dog();
   cat*b  = new cat();

   a->print();
   (*b).print();

   animal*df = new animal();
   df->print();
   animal*cl = new cat();
   cl->print();
*/
  shaid*hg =new trriangle();
  hg->print();
  shaid*ab = new rectangl();
  ab->print();
  shaid*uf = new  circle();
  uf->print();
}