Most Sample Code from "Java How to Program, Fifth Edition" from Deitel and Deitel.

Command line Arguments

Code: Echo.java

• example: java Echo Drink Hot Java
  three arguments
• example: java Echo "Drink Hot Java"
  one argument

Command Line Arguments with Integers

Code: IntCommand.java

• java IntCommand 5
• What happens when you take the parenthesis out around (firstArg+5)?

Discussion on Wrapper classes:

Experimented with Object tool

made an "int" variable and made an "Integer" variable and viewed the difference in Object Tool

From "Java How to Program 5th Edition":
"Each primitive type (such as double) has a corresponding class (such as Double) in package java.lang. These classes (called type-wrapper classes) provide methods for processing primitive type values (such as converting a String to a primitive-type value or vice versa.)" (page 105)
"Each type wrapper class enables you to manipulate primitive type values as objects" (page 485)

Linked-Lists

Overview of a Self-Referential Class:

class Node {
    private int data;
    private Node nextNode;

    public Node ( int data ) { /* constructor body */ }

    public void setData ( int data ) { /* method body */ }

    public int getData () { /* method body */ }

    public void setNext (Node next ) { /* method body */ }

    public node getNext ()  { /* method body */ }
}
     

Code for the linked list:

• Why in ListTest do you use Wrapper types, "Boolean", "Character", and "Integer"?
• What happens when you try primitive types, "boolean", "char", and "int" instead?

Exercise

• Use: http://java.sun.com/j2se/1.4.2/docs/api/index.html
• Click on java.util in the upper left hand box
• Click on LinkedList in the lower left hand box
• A description of LinkedList, the predefined class in the java API (Application Programming Interface) is on the right-hand side
• Convert the ListTest.java file so that you are using the predefined "LinkedList" class.
• You will need functions to add and remove from the beginning of the list and add and remove from the end of the list. Scan for member functions that match this description.
• notice that a different exception is thrown if you are trying to remove from an empty list. You will have to import that exception class.