Shape.py

class Shape:

   'Shape expert class contains shape related attributes and methods'

   count = 0 #Class variable

   #Define constructor using __init__ method

   def __init__(self, c, b): #Constructer receiving two parameters

      self.color = c   #Instance variable

      self.borderWidth = b #Instance variable

      Shape.count += 1 #Increase count

   #Define destructor using __del__ method

   def __del__(self):

      className = self.__class__.__name__

      print ("Destroying ", className )

   #Calculate area of Shape

   def area(self):  

     print ("I dont know how to calculate area")

     return -1

   #Print info of Shape

   def info(self):  

     print ("Color: %s" % self.color)

     print ("Border Width: %s" % self.borderWidth)

   #Define a method

   def displayCount(self):

     print ("Total Shape %d", Shape.count)

   def __str__( self ):

     return "Circle: Color %s Border Width %i"  % (self.color,self.borderWidth)

# define child class

class Circle(Shape):

   PI = 3.14

   def __init__(self, r, c='', b=0): #Constructer receiving two parameters

      self.radius = r   #Instance variable

      self.color = c

      self.borderWidth = b

      #Shape(self,c,b)

   def area(self):

      return self.radius * self.radius  * Circle.PI

class Triangle(Shape):

   def __init__(self, base, height , c='', b=0):

      self.base = base

      self.height = height

      self.color = c

      self.borderWidth = b

   def area(self):

      return (self.base * self.height) /2

   def __str__( self ):

      return "Triangle: Base %d Hieght %d"  % (self.base,self.height) 

class Rectangle(Shape):

   def __init__(self, length, width , c='', b=0):

      self.length = length

      self.width = width

      super(Rectangle,self).__init__(c,b)

   def area(self):

      return self.length * self.length

   def __str__( self ):

      return "Rectangle: Length %d Width %d"  % (self.length,self.width) + " " + super(Rectangle,self).__str__()