// compile with: csc -reference:abstractshape.dll;shapes.dll shapetest.cs class TestClass { static void Main() { Shape[] shapes = { new Square(5, "Square #1"), new Circle(3, "Circle #1"), new Rectangle( 4, 5, "Rectangle #1") }; System.Console.WriteLine("Shapes Collection"); foreach (Shape s in shapes) { System.Console.WriteLine(s); } } } /* Output: Shapes Collection Square #1 Area = 25.00 Circle #1 Area = 28.27 Rectangle #1 Area = 20.00 */