Virtual function for two derived classes


#include <iostream>
using namespace std;

class figure {
protected:
  double x, y;
public:
  void set_dim(double i, double j) {
    x = i;
    y = j;
  }
  virtual void show_area() {
    cout << "No area computation defined ";
    cout << "for this class.\n";
  }
} ;

class triangle : public figure {
  public:
    void show_area() {
      cout << "Triangle with height ";
      cout << x << " and base " << y;
      cout << " has an area of ";
      cout << x * 0.5 * y << ".\n";
    }
};

class rectangle : public figure {
  public:
    void show_area() {
      cout << "Rectangle with dimensions ";
      cout << x << "x" << y;
      cout << " has an area of ";
      cout << x *  y << ".\n";
    }
};

int main()
{
  figure *p; // create a pointer to base type

  triangle t; // create objects of derived types
  rectangle s;

  p = &t;
  p->set_dim(10.0, 5.0);
  p->show_area();

  p = &s;
  p->set_dim(10.0, 5.0);
  p->show_area();  
  
  return 0;
}

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Virtual function for two derived classes : Virtual « Function « C++

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