uses a default operator that sets value types to their zero values and reference types to null. The Point.cs file is part of the GenericPoints projects, which also includes the following file to test out the generic Point class. GenericPoints.cs //---------------------------------------------// GenericPoints.cs (c) 2006 by Charles Petzold //---------------------------------------------using System; class GenericPoints { static void Main() { // Points based on integers Point pti1 = new Point(); Point pti2 = new Point(5, 3); Console.WriteLine(pti1.DistanceTo(pti2)); // Points based on doubles Point ptd1 = new Point(13.5, 15); Point ptd2 = new Point(3.54, 5E-1); Console.WriteLine(ptd2.DistanceTo(ptd1)); // Points based on strings Point pts1 = new Point("34", "27"); Point pts2 = new Point("0", "0"); Console.WriteLine(pts1.DistanceTo(pts2)); } } The program creates two objects of type Point, two objects of type Point, and—amazingly enough—two objects of type Point. Yes, the String class also implements the IConvertible interface, and includes a method named ToDouble that undoubtedly calls Double.Parse. You can also declare objects of type Point because DateTime implements IConvertible as well. But Point

Charles Petzold's .Net Book Zero