Arrays - Part 2

Notes

PA3 - Return - Lessons learned PA3 case study

You should not use System.exit() except under an abnormal end. For each block of code you write (method or structure) there should be one and only one entrance and exit point. breaks, System.exits and other bypasses violate this rule. Do not use them, except for an exceptional end.
You should use named constants for values that have meaning. 100 and 20 in this program should have been constant if used.
There were many methods to help. The majority of students missed the hasWon method. No need to track 100 points.
Don't leave unused parameters or code. Some left the return of the new PigPlayer in playTheGame. If you are not going to use it, remove it.
If you write a method, document it. And use our standards for documentation.

Homework review - Review of questions that are still wrong.

Review of lab - ArrayPlay.java Reading reference (8.2) Note: This is not exactly like your assignment.

The final piece to the header: public static void main( String args[]) What does this mean?

And how do we use it? Command line arguments: Argue.java Book reference (8.12)

Arrays as Reference Types

Passing arrays to methods

Returning arrays from methods

Side effects

Arrays of Objects - What does an array of objects hold?

3 part build

Declare the array
Instantiate the array
Instantiate each object of the array

Example ManyDice.java

Variable Length parameters

VarArgsDemo2.java (Book reference 8.12)

Some specialized Array class tools.

Things to remember about arrays:

Feature	Syntax	Example
Declaration	data-type [] variable-name;	int [] gradeArray; Card [] deck;
Declaration (alternative)	data-type variable-name[];	int gradeArray []; Card deck [];
Initializer list	data-type [] list = { value, value, ... value}	String [] names = { "bob", "ann", "amy", "sue", "sam"};
Instantiation	new data-type[int-value]	intArray = new int [25]; deck = new Card [cardCount];
Instantiation and initialization	new data-type[] { value, value, ... value }	names = new String [] { "bob", "ann", "sue", "sam" }; return new int [] {0};
Referring to the array as a whole	var-name	return deck; intArray = grades; array2.equals(array1); (What do you think this does compares?) arrLength = names.length;
Specialized Arrays methods		java.util.Arrays.fill(grades, 100); java.util.Arrays.equals(section1, section2); java.util.Arrays.sort(names); java.util.Arrays.toString(names)
Referring to array elements	var-name[int-value]	return deck[0]; intArray[ii] = grades[jj]; rank = deck[ii].getRank(); while (intArray[ii] == 5)