comp 170 study guide 1          Dordal     

Here is a summary of the important sections covered. Our book uses what might
be called a "total immersion" approach, and so a *lot* of topics come up in
the first four chapters. I've tried to weed the list down a bit.

As you've no doubt noticed, there are many example projects discussed in
the book. The only one that appears on the exam is the Notebook in chapter 4,
the second version (with a loop). Concepts from other projects will be covered
on the exam, but in isolation, not in the context of the project.
In other words, you do *not* have to study how all these example 
projects work.

Chapter 1: objects, parameters, classes v instances, fields
	This is all at the level of a "first look"; it's all repeated later.

Chapter 2: class definitions, constructors, accessors+mutators = methods
	conditional statements (if, else)
	local variables
	Important sections: 
		2.2	class definitions
		2.3	fields, constructors, and methods
		2.4	parameters
		2.6,7	accessors,mutators
		2.11	if statements
		2.13	local vars
		2.14	fields, parameters, and local vars
	I'm not suggesting any particular exercises from Chapter 2,
	as all that material is so heavily repeated in chapters 3 and 4.
	
	You won't have to write any methods "from scratch" for the exam,
	but you will have to identify return types and parameter types and
	be able to fill in the body of a method.

Chapter 3: abstraction & modularization
	(This is hard to test for on an exam, but it's an important idea.)
	We build the clockDisplay out of *pieces*, in this case, out of
	two numberDisplay objects.
	This chapter also covered Strings, method calls, and object interaction
	Important sections:
		3.6	class diagrams, object diagrams
		3.7	primitive v Object types
		3.8.2	String concatenation
		3.9	Objects creating objects
		3.10	Multiple constructors
	You do NOT need to know about the debugger or the "this" keyword
	for the exam.

	Some selected exercises, numbered as in the 4th edition 
	(with 3rd edition numbers in parentheses):
		3.1
		3.2
		3.3
		3.6
		3.7	> versus >=
		3.8	&& versus ||
		3.20 (3ed: 3.19)	NumberDisplay.increment()
		3.21 (3ed: 3.20)	same
		
Chapter 4: The biggie. The two biggest topics were:
		loops: while, for-each, classic-for (for the latter, reading only)
		arrays & ArrayLists
	There were a few minor new topics mixed in with these two.
		array/ArrayList numbering
		ArrayList: add(), remove(), size()
		i++ versus i=i+1
		null
		anonymous objects
	Important sections:
		4.3	ArrayList library class / Notebook
		4.4	collections
		4.8.1	for-each loop
		4.8.2	while loop
		4.10.3	anonymous objects
		4.12.2-4: arrays
		4.12.6	classic for loops
	Iterators will NOT be on the exam. While you should be able to follow
	for loops, you won't have to write one. You *will* have to write while
	and for-each loops.

	Some selected exercises: 
	(3rd-edition exercise numbers are in parentheses; ignore if you have 4th ed)
		4.3		ArrayList size	
		4.4		ArrayList index values
		4.5		same
		4.6		method call using ArrayList.add()
		4.7		removing items
		4.8		index values after remove()
		4.9		removeNote()
		4.11		why we need loops
		4.12		listNotes()
		4.16	(3d: 4.15)	range checking
		4.17	(3d: 4.16)	while loop to print multiples of 5
		4.21	(3d: 4.20)	modify listNotes()
		4.23	(3d: 4.22)	change indexing
		4.27	(3d: 4.25)	the Club lab
		4.34	(3d: 4.32)	Another Club example, done in class
		4.42	(3d: 4.40)	arrays
		4.43	(3d: 4.41)	arrays
		4.45	(3d: 4.43)	array declaration mistakes
		4.46	(3d: 4.44)	array examples
		4.47	(3d: 4.45)	trick question!
		4.48	(3d: 4.46)	array mistakes
		4.49	(3d: 4.47)	for loop; < versus <=
		4.50	(3d: 4.48)	for-to-while conversion
		4.52	(3d: 4.50) 	while-to-for conversion
	
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Example problems:

These all involve writing part of a program; such problems tend to be hard. 

You will be given Notebook.java (on the website) as a source of examples.

The exam WILL also have easier problems such as:
        format the following with reasonable indentation
        correct the syntax errors
        what does this program do? What is the output?
        Suggest a class (fields & methods) to accomplish a given task


1. Suppose we have an 
	ArrayList notes
All the actual notes are String objects.
Write a loop to concatenate all the strings into one big one.
	String result = "";
	int i = 0;
	while ( i<notes.size() ) {
	    ????
	    i = i+1;
	}


2. Write a loop to add up the numbers from 1 to N. 

3. Finish a method printMultiple(n,ch) that takes two parameters, 
an int n and a char ch, and prints n copies of that character: 
printMultiple('a', 4) should yield aaaa. 

	public void printMultiple ( _____ n, _____ ch) {
	
	}
	

4. *Using* the method printMultiple() above, write a loop to draw
        *
        ***
        *****
        *******
(each row has two more *'s than the previous row.)


5. Write a method that reverses a string:
        public String reverse (String s) {
        }
Hint: let n = s.length(). The letters of s are s.charAt(n-1) down to 
s.charAt(0). Append these (with +) in turn to an initially empty string.