Create a class named circle with fields named radius, diameter, and area. include a constructor that sets the radius to 1 and calculates the other two values. also include methods named setradius() and the setradius() method not only sets the radius, but it also calculates the other two values. (the diameter of a circle is twice the radius, and the area of a circle is pi multiplied by the square of the radius. use the math class pi constant for this calculation.)