Debugging

[stevanity]

Hello guyz!
Im conducting a debugging contest...

Im writing some questions... I wrote a code implementing virtual functions..

Im not sure where to include bugs here.. Can anyone help me add bugs to this code??
Please bugs must make people think.. THey must not just be syntactical errors..

Thank you..
Output wil be given to the debugger.. and he will asked to debug the code to produce desired result Thanks!

#include <iostream>
   using namespace std;


   class Shape
   {
   public:
      Shape()
      {}

      virtual long GetArea()
      {
        cout<<"Area";
      }
      virtual long GetPerimeter()
      {
        cout<<"Perimeter";
      }
      virtual void Draw() = 0;

   };

   void Shape::Draw()
   {
      cout << "Shape Drawn!!";
   }

   class Circle : public Shape
   {
   private:
      int radius;
      int circumference;
   public:
         Circle(int rad):radius(rad)
         {
         }

         long GetArea() { 
         return 3 * radius * radius; 
         }
         long GetPerim() { 
         return 9 * radius; 
         }
         void Draw()
         {
            cout << "Circle drawing routine here!\n";
         }
   };

   class Rectangle : public Shape
   {
   private:
      int Width;
      int Length;

   public:
         Rectangle(int len, int width):
            Length(len), Width(width)
          {}

         long GetArea() 
         { 
          return Length * Width; 
         }
         long GetPerim() 
         {
          return 2*Length + 2*Width; 
         }
         virtual int GetLength() 
         {  
            return Length; 
         }
         virtual int GetWidth() 
         { 
            return Width; 
         }
         void Draw()
         {
            for (int i = 0; i<Length; i++)
            {
               for (int j = 0; j<Width; j++)
                  cout << "x ";

               cout << "\n";
            }
          
         }
   };

   class Square : public Rectangle
   {
   public:
         Square(int len):
            Rectangle(len,len)
            {}
         Square(int len, int width):
             Rectangle(len,width)

             {
                if (GetLength() != GetWidth())
                   cout << "Error, not a square... a Rectangle??\n";
             }

         long GetPerim() {
          return 4 * GetLength();
         }
   };

   int main()
   {
      int choice;

      Shape * sp;

      while (1)
      {
         cout << "1.Circle\n2.Rectangle\n3.Square\n4.Quit\nEnter Choice.. ";
         cin >> choice;

         switch (choice)
         {
            case 1: sp = new Circle(5);
            break;
            case 2: sp = new Rectangle(4,6);
            break;
            case 3: sp = new Square (5);
            break;
         }
         if (choice==4)
            break;

         sp*Draw();
         cout << "\n";
      }
     return 0;
 }

[thines01]

Remove the word public from a couple of the classes.
Put an =0 on a constructor.
Use the same shape twice on two of your choices.

[FortranIV]

Well, the most obvious bug is that you don’t have a default case for your switch, and you don’t bounds check the user input. Also, you don’t use Pi to calculate the area of the circle. You don’t use Pi to calculate the perimeter, but if you did, the formula is incorrect.

If I were trying to add more bugs, I would want the user to input the length and width of the shapes. It is very easy to have bug in you code when you are validating or handling data. An example would be reversing the height and width of a rectangle. You could also allow non-integer input from the user. That would make things more interesting.

[thines01]

@FortranIV. Good suggestions.

[stevanity]

Thanks guyz!!

[Zcool31]

Write a templated class that makes some assumptions about the template type. Instantiate it with a type that violates said assumptions. Watch the debugger point you to the constructor when the error is in the instantiation.