2. (4 points) Write a Circle class that has the following private member variables: radius : a double pi : a double initialized with the value 3.14159 The class should have the following member functions: Default Constructor. A default constructor that sets radius to 0.0. Constructor. Accepts the radius of the circle as an argument. setRadius. A function which sets the radius variable. getRadius. Returns the radius. get Area. Returns the area of the circle, which is calculated as area = pi * radius * radius getDiameter. Returns the diameter of the circle, which is calculated as diameter = radius * 2 get Circumference. Returns the circumference of the circle, which is calculated as circumference = 2 * pi * radius Write a program that demonstrates the Circle class by asking the user for the circle's radius, creating a Circle object, and then reporting the circle's area, diameter, and circumference