Write a program that computes the area of a circular region (the shaded area in the diag...

Write a program that computes the area of a circular region (the shaded area in the diagram), given the radii of the inner and the outer circles, r_i and r_o, respectively.

We compute the area of the circular region by subtracting the area of the inner circle from the area of the outer circle. Define a Circle class that has methods to compute the area and circumference. You set the circle’s radius with the setRadius method or via a constructor.