Add "Circle Caluclator" example

Signed-off-by: Ercan Ersoy <ercanersoy@ercanersoy.net>

Author: ercanersoy

README.md

@@ -7,4 +7,5 @@ Copyright (c) 2020 Ercan Ersoy
 ## Examples List
 
 * [Hello World](hello-world)
-* [User Input](user-input)
+* [User Input](user-input)
+* [Circle Calculator](circle-calculator)

circle-calculator/circle-calculator.py

@@ -0,0 +1,12 @@
+pi = 3.14
+
+radius = int(input("Radius of circle: "))
+
+circumference = radius * 2 * pi
+area = pow(radius, 2) * pi
+
+print("Circumference: ", end="")
+print(circumference)
+
+print("Area: ", end="")
+print(area)