Question

Using Python

Write the following well-documented (commented) program.

Create a class called Shape that has a method for printing the area and the perimeter.

Create three classes (Square, Rectangle, and Circle) which inherit from it.

• Square will have one instance variable for the length.
• Rectangle will have two instance variables for the width and height.
• Circle will have one instance variable for the radius.
• The three classes will have methods for computing the area and perimeter of its corresponding shape.

Write a main method to test your program that uses objects of the classes you created.

• It should ask the user for the length of a square, the width and height of a rectangle, and the radius of a circle.
• It should then print out the area and perimeter of the three shapes.

A sample run would be as follows.

Enter the length of a square: 7
The area is 49.00 and perimeter is 28.00.
Enter the width of a rectangle: 5
Enter the height of a rectangle: 6
The area is 30.00 and perimeter is 22.00.
Enter the radius of a circle: 4
The area is 50.24 and perimeter is 25.12.

Answer 1

"""
  Python program to illustrate concepts of classes and inheritence using shape class
"""

import math as M

class Shape(object):
  def __init__(self):
    self.area = 0
    self.perimeter = 0

  def printAreaPerimeter(self):
    print("The area is ", self.area, " and perimeter is ",self.perimeter)

class Square(Shape):
  def __init__(self, length):
    self.area = length**2
    self.perimeter = length*4

class Rectangle(Shape):    
  def __init__(self, width, height):
    self.area = width*height
    self.perimeter = 2*(height + width)

class Circle(Shape):
  def __init__(self, radius):
    self.area = round(M.pi*(radius**2), 2)
    self.perimeter = round(2*M.pi*radius, 2)

def main():

  l = int(input("Enter the length of a square: "))
  sqr = Square(l)
  sqr.printAreaPerimeter()

  w = int(input("Enter the width of a rectangle: "))
  h = int(input("Enter the height of a rectangle: "))
  rect = Rectangle(w, h)
  rect.printAreaPerimeter()

  r = int(input("Enter the radius of a circle: "))
  circ = Circle(r)
  circ.printAreaPerimeter()

if __name__ == '__main__':
  main()

# Program ends here