# Solution Exercise 44: class circle en python

Sep 4, 2021

#### Exercise 44. Circle class

1 - Define a Circle class allowing to create a circleC (O, r) with center O(a, b) and radius r using the constructor:

``    def __init__(self,a,b,r):                 self.a = a                 self.b = b                 self.r = r``

2 - Define a Area() method of the class which calculates the area of ​​the circle.
3 - Define a Perimeter() method of the class which allows you to calculate the perimeter of the circle.
4 - Define a testBelongs() method of the class which allows to test whether a point A(x, y) belongs to the circle C(O, r) or not.

#### Solution

``from math import piclass Circle:    def __init__(self, a, b, r):        self.a = a        self.b = b        self.r = r    def perimeter (self):        return  2 * pi * self.r    def area (self):        return  pi * self.r**2        # form of the cercle equation     def formEquation (self, x, y):        return (x-self.a)**2 + (y-self.b)**2 - self.r**2        # method to test if given point blong to the circle or not     def test_belong (self, x, y):        if (self.formEquation (x, y) == 0):            print ("the point: (", x, y, ") belongs to the circle C")        else:            print ("the point: (", x, y, ") does not belong to the circle C")# Creating of an instance objectC = Circle (1,2,1)print ("the perimeter of the circle C is:", C.perimeter() )print ("the area of circle C is:", C.area())# we test if the point(1,1) belong to the circle or notC.test_belong(1,1) # The output is:#the perimeter of the circle C is: 6.283185307179586#the area of circle C is: 3.141592653589793#the point: ( 1 1 ) belongs to the circle C``
Younes Derfoufi
my-courses.net

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##### One thought on “Solution Exercise 44: class circle en python”
1. import math
class Circle:
def __init__(self, a, b, r):
self.a = a
self.b = b
self.r = r
def area(self):
return math.pi * self.r**2
def perimeter(self):
return 2*math.pi*self.r
def testBelongs(self, x, y):
if (x – self.a)**2 + (y – self.b)**2 == self.r**2:
return print(f"{(x,y)} points are belongs to the circle(O,{self.r})"
f" with center O{self.a,self.b} ")
else:
return print(f"{(x, y)} points are not belongs to the circle(O,{self.r})"
f" with center O{self.a, self.b} ")