Week 5: Week of Sept 24

Explanation of Lab 3

	Collatz sequences
	
	7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1
	
	N=15: max=160
	N=25: len=23
	
	25, 76, 38, 19, 58, 29, 88, 44, 22, 11, 34, 
	17, 52, 26, 13, 40, 20, 10,  5, 16,  8,  4, 
	 2,  1 
	 
	N=27: Max = 9232, len=111
	
	classic-for loops: know # of iterations ahead of time
	for:each loop: # of iterations is the length of the list!
	
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Arrays
		
	Allocating arrays v allocating array elements
	
	classic for-loops:
		initializing an array of ints to 0
		adding the elements of an array
		finding the max of an array
		counting selected elements of an array
		
	classic for-loops v for:each loops
	was the classic for-loop really *designed* for arrays?
	
	for:each loop: no access to the numeric position in the list!
	
	classic-for / while equivalence
	
	for:each and arrays

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Weblog-analyzer

	overview of program
		input: how much do we really have to know?
	
	how would we do it with an ArrayList?

	Adding Weekly counts

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Wednesday:

	chart version, fixed (rectangles grow downwards!)
	
	arrays v ArrayList:
		get/set interface is awkward.
		For many lists, though,we NEVER use it:
			insert using .add(item)
			access using for:each loops
	
	How new Foo(...) works
		memory view of object creation and of arrays

	ArrayList expansion, NumList
	
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Friday:

	Example demoing how "real" ArrayLists handle growth
	Sizes: 10, 16, 25, 38, 58, 88, 133, 200
	next size = floor(1.5*prev_size) + 1;

Hard loops:
	loops that MODIFY the list structure.
	Example: in the MailSystem, getNextMessage(user) found the next
	message for the user, DELETED IT from the master list,
	and returned it.
	
However, returning a new list is NOT so hard:

	notes: ArrayList<String>
	
	---------
	
	matches = new ArrayList<String>();
	
	for (String note : notes) {
	    if (note.contains(str)) {
	    	matches.add(note);
	    }
	}
	
	
	
My own NumList

	using it in the program