CSC297.Java 2003F, Class 11: Implementing Vectors

Admin:
* Why can't Alex be on time?  Too much drinking last night.
* Any thoughts on how the guided reading is going?
* Tell me about your word statistics programs
* Homework:
  * Write set
  * Write a few more procedures (see docs for ideas)
  * Rewrite your word statistics program to use MyVector
 
Overview:
* Primary methods
* Implementation strategy
* Details of implementation
* Testing (one two three)

Morals from Yvonne's Example:
* Be careful about array bounds
* You are not required to use System.exit(0), but it's a good idea.
* Helper procedures are helpful.
* It's sometimes dangerous to handle lots of different exceptions at once.  (Hmmm ... Sam should teach you about exceptions.)
* Syntax and Semantics of compareTo.
	alpha.compareTo(beta)
  * Returns a negative number is alpha precedes beta
  * Returns a positive number if alpha follows beta
  * Returns 0 if alpha = beta

Today's project: Implement Java-style Vectors
* Building blocks: Arrays and fun Java techniques we know already.
* Reminder: A vector is an "expandable" array.
* Step one: Decide on key operations
  * vec.add(Object val) -- Adds to the end
  * vec.set(int pos, Object newVal) -- sets a value at the specified position
    * Something to think about
	vec = new MyVector();
	vec.replace(5, "Hello");
    * If previous values are unset, sets them to null.
  * vec.get(int pos) -- Get the value at a specified position
  * vec.length() -- Get the length of a vector
  * Constructor
* toSTring
  * E.g., suppose [1,2,3]
    "[" + "1" + "," + "2" + "," + "3" + "]"