need help

[satan]

I need a help with the program to test the insertion, deletion, search, copyList, and the copy constructor operations for an object in the class UnorderedLinkedList.

These are my classes:



public class UnorderedLinkedList extends LinkedListClass
{

public UnorderedLinkedList()
{
super();
}

public UnorderedLinkedList(UnorderedLinkedList otherList)
{
super(otherList);
}

//Method to determine whether searchItem is in
//the list.
//Postcondition: Returns true if searchItem is found
// in the list; false otherwise.
public boolean search(DataElement searchItem)
{
LinkedListNode current; //variable to traverse the list
boolean found;

current = first; //set current to point to the first
//node in the list

found = false; //set found to false

while(current != null && !found) //search the list
if(current.info.equals(searchItem)) //item is found
found = true;
else
current = current.link; //make current point to
//the next node
return found;
}


//Method to delete deleteItem from the list.
//Postcondition: If found, the node containing
// deleteItem is deleted from the
// list. Also first points to the first
// node, last points to the last
// node of the updated list, and count
// is decremented by 1.
public void deleteNode(DataElement deleteItem)
{
LinkedListNode current; //variable to traverse the list
LinkedListNode trailCurrent; //variable just before current
boolean found;

if(first == null) //Case 1; the list is empty
System.err.println("Cannot delete from an empty list.");
else
{
if(first.info.equals(deleteItem)) //Case 2
{
first = first.link;

if(first == null) //the list had only one node
last = null;
count--;
}
else //search the list for the node with the given info
{
found = false;
trailCurrent = first; //set trailCurrent to point to
//the first node
current = first.link; //set current to point to the
//second node

while(current != null && !found)
{
if(current.info.equals(deleteItem))
found = true;
else
{
trailCurrent = current;
current = current.link;
}
}//end while

if(found) //Case 3; if found, delete the node
{
count--;
trailCurrent.link = current.link;

if(last == current) //node to be deleted was
//the last node
last = trailCurrent; //update the value of last
}
else
System.out.println("Item to be deleted is "
+ "not in the list.");
}//end else
}//end else
}//end deleteNode
}




public abstract class LinkedListClass
{
protected class LinkedListNode
{
DataElement info;
LinkedListNode link;
}

protected LinkedListNode first; //variable to store the
//address of the first
//node of the list
protected LinkedListNode last; //variable to store the
//address of the last
//node of the list
protected int count; //variable to store the number of nodes
//in the list


//default constructor
//Initializes the list to an empty state.
//Postcondition: first = null, last = null,
// count = 0
public LinkedListClass()
{
first = null;
last = null;
count = 0;
}

//Method to determine whether the list is empty.
//Postcondition: Returns true if the list is empty;
// false otherwise.
public boolean isEmptyList()
{
return (first == null);
}

//Method to initialize the list to an empty state.
//Postcondition: first = null, last = null,
// count = 0
public void initializeList()
{
first = null;
last = null;
count = 0;
}

//Method to output the data contained in each node.
public void print()
{
LinkedListNode current; //variable to traverse the list

current = first; //set current so that it points to
//the first node
while(current != null) //while more data to print
{
System.out.print(current.info + " ");
current = current.link;
}
}//end print

//Method to return the number of nodes in the list.
//Postcondition: The value of count is returned.
public int length()
{
return count;
}


//Method to return a reference of the object containing
//the data of the first node of the list.
//Precondition: The list must exist and must not be empty.
//Postcondition: The reference of the object that
// contains the info of the first node
// is returned.
public DataElement front()
{
DataElement temp = first.info.getCopy();
return temp;
}

//Method to return a reference of object containing
//the data of the last node of the list.
//Precondition: The list must exist and must not be empty.
//Postcondition: The reference of the object that
// contains the info of the last node
// is returned.
public DataElement back()
{
DataElement temp = last.info.getCopy();
return temp;
}

//Method to determine whether searchItem is in the list.
//Postcondition: Returns true if searchItem is found
// in the list; false otherwise.
public abstract boolean search(DataElement searchItem);


//Method to insert newItem in the list.
//Postcondition: first points to the new list
// and newItem is inserted at the
// beginning of the list. Also,
// last points to the last node and
// count is incremented by 1.
public void insertFirst(DataElement newItem)
{
LinkedListNode newNode; //variable to create the
//new node

newNode = new LinkedListNode(); //create the new node
newNode.info = newItem.getCopy(); //assign a copy of
//newItem to the node
newNode.link = first; //insert newNode before first
first = newNode; //make first point to the
//actual first node

if(last == null) //if the list was empty, newNode is
//also the last node in the list
last = newNode;

count++;
}

//Method to insert newItem at the end of the list.
//Postcondition: first points to the new list and
// newItem is inserted at the end
// of the list. Also, last points to
// the last node and
// count is incremented by 1.
public void insertLast(DataElement newItem)
{
LinkedListNode newNode; //variable to create the new node

newNode = new LinkedListNode(); //create the new node
newNode.info = newItem.getCopy(); //assign a copy of
//newItem to the node
newNode.link = null; //set the link field of
//newNode to null

if(first == null) //if the list is empty, newNode is
//both the first and last node
{
first = newNode;
last = newNode;
}
else //if the list is not empty, insert newNode after last
{
last.link = newNode; //insert newNode after last
last = newNode; //set last to point to the actual last node
}

count++;
}//end insertLast



//Method to delete deleteItem from the list.
//Postcondition: If found, the node containing
// deleteItem is deleted from the
// list. Also first points to the first
// node, last points to the last
// node of the updated list, and count
// is decremented by 1.
public abstract void deleteNode(DataElement deleteItem);

//Method to return a reference of the copy of otherList.
private void copy(LinkedListClass otherList)
{
LinkedListNode newNode; //variable to create a node
LinkedListNode current; //variable to traverse the list

first = null; //make this list empty

if(otherList.first == null) //otherList is empty
{
first = null;
last = null;
count = 0;
}
else
{
count = otherList.count;
current = otherList.first; //current points to the
//list to be copied

//copy the first element
first = new LinkedListNode(); //create the node
first.info = current.info.getCopy(); //copy the info
first.link = null; //set the link field of
//the node to null
last = first; //make last point to the first node
current = current.link; //make current point to the next
//node of the list being copied

//copy the remaining list
while(current != null)
{
newNode = new LinkedListNode();
newNode.info = current.info.getCopy();
newNode.link = null;
last.link = newNode;
last = newNode;
current = current.link;
}//end while
}//end else
}//end copy


//Method to return a reference of the copy of otherList.
public void copyList(LinkedListClass otherList)
{
if(this != otherList) //avoid self-copy
copy(otherList);
}

//copy constructor
public LinkedListClass(LinkedListClass otherList)
{
copy(otherList);
}//end copy constructor
}



import java.io.*;
import java.util.*;

public class TestProgUnorderedLinkedList
{
static BufferedReader keyboard = new
BufferedReader(new InputStreamReader(System.in));

public static void main(String[] args) throws IOException
{
UnorderedLinkedList list
= new UnorderedLinkedList();
UnorderedLinkedList tempList =
new UnorderedLinkedList();
IntElement num = new IntElement();

StringTokenizer tokenizer;

int position;

System.out.print(" Enter 8 integers on the " + "same line: ");
System.out.flush();

tokenizer = new
StringTokenizer(keyboard.readLine());

num.setNum(Integer.parseInt(tokenizer.nextToken()) );

while (tokenizer.hasMoreTokens())
{
num.setNum(Integer.parseInt(tokenizer.nextToken()) );
list.insertLast(num);
}

System.out.println();
System.out.print("The list you " + "entered is: ");
list.print();
System.out.println();
System.out.println("Length of list: " + list.length());

tempList.copyList(list);

System.out.print("Enter the num to " + "be deleted: ");
System.out.flush();
num.setNum(Integer.parseInt(keyboard.readLine()));
System.out.println();

tempList.deleteNode(num);
System.out.println("After deleting " + num + " the node, tempList:");
tempList.print();
System.out.println();
System.out.println("Length of list: " + tempList.length());

System.out.print("Enter the search " + "item: ");
System.out.flush();

num.setNum(Integer.parseInt(keyboard.readLine()));
System.out.println();

if(tempList.search(num) != -1)
System.out.println("Item found in " + "the list");
else
System.out.println("Item not found");

System.out.print("The list temp: ");
tempList.print();
System.out.println();
System.out.println("Length of list: " + tempList.length());
}
}

[r035198x]

You know with code tags, the code becomes more readable.
In java LinkedLists the trick is the design of the node. Here is how I would do it:

class LinkedListNode {
    private Object data;
    private Listnode next;
 
    public LinkedListNode(Object d) {
    this(d, null);
    }
 
    public LinkedListNode(Object d, LinkedListNode n) {
    data = d;
    next = n;
    }
 
    public Object getData() {
        return data;
    }
 
    public LinkedListNode getNext() {
        return next;
    }
 
 
    public void setData(Object ob) {
        data = ob;
    }
 
    public void setNext(LinkedListNode n) {
        next = n;
    }
}
public class TheList {
    LinkedListNode head;
    LinkedListNode tail;
 
    public static void main(String[] args) {
        TheList linkedList = new TheList();
    }
    public TheList() {
        head = null;
        tail = null;
    }
    public TheList(LinkedListNode head, LinkedListNode tail) {
        this.head head;
        this.tail = tail;
    }
 
    public void addLast(LinkedListNode node) {
        if(head == null) {
            head = node;
        }
        else if(tail == null) {
            tail = node;
        }
        else {
            tail.setNext(node);
        }
    }
 
    public boolean contains(LinkedListNode node) {
        boolean found = false;
        LinkedListNode current = head;
        if(current == null) {
            found = false;
        }
        else {
            while(current != null && !found ) {
                if(current.getData().equals(node.getData())) {
                    found = true;
                }
                current = current.getNext();
            }
        }
        return found;
    }
 
    public void addAfter(LinkedListNode nodeInList, LinkedListNode nodeToAdd) {
        if(!contains(nodeToAdd)) {
            System.out.println("Failed to add..");
        }
        else {
            LinkedListNode current = head;
            boolean positionReached = false;
            while(!positionReached) {
                if(current.getData().equals(nodeInList)) {
                    positionReached = true;
                }
            }
            LinkedListNode temp = current.getNext();
            current.setNext(nodeToAdd);
            nodeToAdd.setNext(temp);
 
        }
    }
    // the rest of the methods should now be easy
 
}

perhaps better approaches can be found here
http://www.cs.jhu.edu/~pari/600.107/Horstmann/slides/Ch19/ch19.html
http://www.javacommerce.com/displaypage.jsp?name=javadata2.sql&id=18214#Linked _Lists