CpSc 210, Section 1
                             Assignment 8 
                            November 13, 2002      



Due:  Tuesday, November 19, at 11:59 p.m.  

Assignment:  Extend Bailey's BinaryTree class to include a recursive equals
	method.


Total point value of assignment:  50 points
Not accepted late.

This assignment is to be done INDIVIDUALLY.

Assignment:  Design and implement a class, BTextended as an extension of
     Bailey's BinaryTree, which must be stored in a file named
     BTextended.java.  (10 point deduction for failure to name file 
     correctly!)  

Bailey's BinaryTree code may be found at the "View the Local Source"
link from

     http://www.mhhe.com/javastructures


The BinaryTree interface is given on pages 190-191 of Java Structures.
Bailey's code does not include an equals method, so you are to supply it.
You may include any private methods you want.

You will want to import structure.BinaryTree.

The signature of the equals method is

    	public boolean equals ( Object other );
        // post:  returns true if and only if this is the same as other.

You will want to check that other is an instance of BTextended and then
cast it to another variable of type BTextended.  (as in Assignment #4)

Grading Rubric:

     5 pts. reasonable attempt to solve problem as assigned
	        (Method must be recursive.)
     5 pts. also compiles
     5 pts. style standards (includes clarity)

            Now that we are dealing with references, the comment after
            exit from "while" loops is especially important.  The comment
            on an "else" is also useful.  One point will be deducted
            for each missing comment (maximum of 5) in the code
            that you write.  (Yes, we know Bailey does not have these
            and you cannot correct his code, but you can write yours
            in this manner.)
  
            Don't forget your pre- and post-conditions.
 
            Do throw an IllegalArgumentException if precondition not met.

    The following 35 points are available only for code that compiles 
    without error.   Some considerations are:

    20 pts. code of equals method returns correct answer
     5 pts. evidence that  your test driver (main method) systematically
	        checks for errors.

    The following 10 points are available only for code that 
    returns correct answer:

     5 pts. growth rate of equals method is best possible 
     5 pts. elegance of code