$1)$ Define a class for a circle that has fields for radius, area, and diameter.

$2)$ Create methods in the class to get and set data and to compute diameter, compute area, and

get diameter and area.

$3)$ Include a constructor where you can pass in the radius.

$4)$ Write a test program that instantiates an object using the Circle class, sets the radius and

displays the diameter and area using the console.