Rob, "is-A" relationship used on inheritance to describe parent/child realtionship. eg : Occupation class as parent class, Programmer, CabDriver being child class of Occupation. in Java we say Programmer extends Occupation CabDriver extends Occupation we then decribe the relationship like : Programmer is-A Occupation CabDriver is-A Occupation [ July 21, 2003: Message edited by: chi Lin ]
not so smart guy still curious to learn new stuff every now and then
Is-A is a helpful way to hunt for opportunities for inheritance, but it is not the only way and it is not always right and inheritance is not the only way to "be" something else. So if you see something in the real world that "is a" something else but inheritance makes no sense in code, listen to the code. When using inheritance, you should also be aware of the Liskov Substitution Principle. Do a Google search for papers and see how it complicates the simple "Is-A" some times.
A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi