Defining a class in python

Following syntax to define a class

class ClassName:
     initializer
     methods

example

import math

class Circle:
    # Construct a circle object
    def __init__(self, radius = 1):
        self.radius = radius
        
    def getPerimeter(self):
        return 2 * self.radius * math.pi
    
    def getArea(self):
        return self.radius * self.radius * math.pi
    
    def setRadius(self, radius):
        self.radius = radius
   

 

 

testCircle.py

from Circle import Circle

def main():
    # Create a circle with radius 1
    circle1 = Circle()
    print("The area of the circle of radius", circle1.radius,"is",circle1.getArea())

    # Create a circle with radius 25
    circle2 = Circle(25)
    print("The area of the circle of radius",circle2.radius,"is", circle2.getArea())

    # Create a circle with radius 125
    circle3 = Circle(125)
    print("The area of the circle of radius",circle3.radius,"is",circle3.getArea())

    # Modify circle radius
    circle2.radius = 100 # or circle2.setRadius(100)
    print("The area of the circle of radius",circle2.radius,"is",circle2.getArea())

main() # Call the main function