SAMS Teach Yourself Programming with Java™ in 24 Hours, FOURTH EDITION

Workshop: Creating a Subclass

To see an example of inheritance at work, you will create a class called Point3D that represents a point in three-dimensional space. A two-dimensional point can be expressed with an (x,y) coordinate. Applets use an (x,y) coordinate system to determine where text and graphics should be displayed. Three-dimensional space adds a third coordinate, which can be called z.

The Point3D class of objects should do three things:

• Keep track of an object's (x,y,z) coordinate.
• Move an object to a new (x,y,z) coordinate when needed.
• Move an object by a certain amount of x, y, and z values as needed.

Java already has a standard class that represents two-dimensional points; it's called Point. It has two integer variables called x