cs230 Lecture Notes
Week 9 Tuesday


Implementation diagrams and the really big picture.


Class and instance variables
----------------------------

instance variable: every instance has one.  You can
	 refer to them from object methods or, anywhere,
	 using dot notation

class variable: there's only one.  You can refer to it
         from any method in the class, or from outside
	 the class using dot notation

Don't let the compiler lead you by the nose!



Iterators
---------

We often want to allow client code to traverse a data
structure without completely breaking down the wiggly
line of abstraction.

Section 10.9 explains one way of accomplishing that:

1) the data structure provides a method that returns
   an Iterator object

2) Iterator is an abstract class defined in java.util

3) the methods of Iterator are

   hasNext and next

Another example: there is a LinkedList class in java.util
that has a method named listIterator that returns an object
with type ListIterator which is a member of the abstract
class Iterator which you can use to traverse the LinkedList!


Trees -- Chapter 10
-----

tree node = cargo + 2 references

FAT applies to tree nodes, too


In this case, probably no sentinel class.  Just tree nodes,
which will be objects with type Tree.

Vocabulary:

node, root, leaf, child, parent, level


Read all of Chapter 10 before Thursday so you can get started
on the next assignment during lab.