write a c++ program that prompts the user for the radius of a circle and calculates and displays the area.

- create a class, Circle : has a private data member 'radius' of type double

- in main()

1. instantiate an object of class Circle

2. prompt the user to enter the radius of a circle, store this value in the instantiated object -- how?

3. call a global function that calculates and returns the area of a circle using the Circle object as the argument for the function call

4. display the radius and the area of the circle

This shouldn't be complicated