The IShape interface declares int Area(). Create a Rectangle class (constructor takes width and height, Area() returns width * height) and a Square class (constructor takes side, Area() returns side * side), both implementing IShape. The tester stores them in one IShape[] and totals their areas. Do NOT write a Main method.

For { Rectangle(2, 3), Square(4) } the total is 6 + 16, so the program prints:
22