Need help with some code ... Searching a tree and inserting data

Question

I'm trying to write code for the addIterative method below.
My problem is that I also need to search the list or node to see if the word exists.
The method add(word,line,position,iterative) validates the parameters; and, in order to update the tree and/or any relevant linked-list, calls either the incomplete method addIterative(word,line,position) or the incomplete method addRecursive(word,line,position). Note the following: if the word is not contained currently in the tree, then all of the (word,line,position) triplet needs to be added to the data structure; otherwise, only the (line,position) pair needs to be added to the data structure. The result must be the same regardless of the algorithmic strategy employed.
any suggestions would be greatly appreciated, new to java, and very lost.
regards,
Jimmy
* Write a description of class Tree091 here.
* @author (your name)
* @version (a version number or a date)
class Tree091 /*(i.e., WordTree)*/
{ private char[] word=null;
private List091 list=null;
private Tree091 precursor=null; /*(i.e., leftSubTree)*/
private Tree091 successor=null; /*(i.e., rightSubTree)*/
public Tree091(char[] word,
List091 list,
Tree091 precursor, /*(i.e., lexicographically < word)*/
Tree091 successor) /*(i.e., lexicographically > word)*/
{ if (word==null) return;
if (word.length<1) return;
if (list==null) return;
this.word=word;
this.list=list;
this.precursor=precursor;
this.successor=successor;
public void add(char[] word,
int line,
int position,
boolean iterative)
{ if (word==null) return;
if (word.length<1) return;
if (line<0) return;
if (position<0) return;
if (iterative)
this.addIterative(word,line,position);
else
this.addRecursive(word,line,position);
private void addIterative(char[] word,
int line,
int position)
/* something goes here*/
private void addRecursive(char[] word,
int line,
int position)
/* something goes here*/
private int compare(char[] array1,
char[] array2)
{ if (array1==null) return -2;
if (array2==null) return -2;
int length1=array1.length;
if (length1==0) return -2;
int length2=array2.length;
if (length2==0) return -2;
int minLength=length1<length2?length1:length2;
for (int i=0; i<minLength; i++)
{ if (array1[i]<array2) return -1;
if (array1[i]>array2[i]) return 1;
return length1==length2 ? 0 : length1<length2 ? -1 : 1;
public boolean contained(char[] word)
{ int compare=compare(this.word,word);
if (compare==1&&this.precursor!=null)
return this.precursor.contained(word);
if (compare==0) return true;
if (compare==-1&&this.successor!=null)
return this.successor.contained(word);
return false;
public int listNodeCount(boolean iterative)
/* something goes here*/
return 24;
public int maximumWordLength(int currentLength)
/* something goes here*/
return 25;
public String toString()
{ String string="";
if (this.precursor!=null) string+=this.precursor;
string+="\""+(new String(this.word))+"\""+this.list;
if (this.successor!=null) string+=this.successor;
return string;
public int treeNodeCount()
/* something goes here*/
return 26;
public String wordArray(int length)
/* something goes here*/
return "hey hey wordarray";

Answer 1

hey,
ok, wow, that was intense, my brain hurts!!!!
And now I've got to go do a graduate program test, argh!!!
A problem I keep getting is trying to figure out what my lecturer is doing in the start of the Tree091 class,
that is, I can see that he is constructing the list and tree but it appears that he is doing it all at the same time, and I'm getting confused with what actually gets inserted into the list, and do we insert the word, line and position, or just the line and position?
Also, I didnt use a 'while loop', I'm not sure how, but I found a 'for loop' in the text book, what do you think of it? Is it ok for now?
And I'm getting an error at this line:
Tree091 ins = new Tree091(char[] word); // getting error '.class' expected here
any ideas?
heres what I've got so far:
private void addIterative(Comparable char[] word,int line, int position){
// Insert char[] word into the this BST     
     int direction = 0;     
     Tree091 parent = null, curr = root;
     for (;;) {     
          if (curr == null) {
               Tree091 ins = new Tree091(char[] word); // getting error '.class' expected here
               // word found so we call insertList method
               insertList091(line, position, List091 precursor);
               if (root) == null)
                    root = ins;
               else if (direction < 0)     
                    parent.left = ins;
               else // direction > 0
                    parent.right = ins;
               return;
          direction = elem.compareTo(curr.element);
          if (direction == 0)
               return;
          parent = curr;
          if (direction < 0)
               curr = curr.left;
          else // direction > 0
               curr = curr.right;
}And heres an attempt at the insertList method
private void insertList(char[] word, int line, int position, List091 precursor){
// Insert line and position at a given point in this List091, either after the node
// precursor, or before the first node if precursor is null
// Looking at assignment question we may need a double linked list
     List091 ins = new List091 (char[] word, line, position, null);
     if precursor == null) { //insert before first node (if any).
          ins.successor = first;
          first = ins;
     } else {
          ins.successor = precursor.successor;
          precursor.successor = ins;
}How far off am I Joachim?
cheers,
Jimmy
ps. heres the tree091 class again:
class Tree091 /*(i.e., WordTree)*/
{ private char[] word=null;
  private List091 list=null;
  private Tree091 precursor=null; /*(i.e., leftSubTree)*/
  private Tree091 successor=null; /*(i.e., rightSubTree)*/
  public Tree091(char[] word,
                 List091 list,
                 Tree091 precursor, /*(i.e., lexicographically < word)*/
                 Tree091 successor) /*(i.e., lexicographically > word)*/
  { if (word==null) return;
    if (word.length<1) return;
    if (list==null) return;
    this.word=word;
    this.list=list;
    this.precursor=precursor;
    this.successor=successor;
  public void add(char[] word,
                  int line,
                  int position,
                  boolean iterative)
  { if (word==null) return;
    if (word.length<1) return;
    if (line<0) return;
    if (position<0) return;
    if (iterative)
      this.addIterative(word,line,position);
    else
      this.addRecursive(word,line,position);
  private void addIterative(char[] word,
                            int line,
                            int position)
    /* students to complete */
  private void addRecursive(char[] word,
                            int line,
                            int position)
     /* students to complete */
  private int compare(char[] array1,
                      char[] array2)
  { if (array1==null) return -2;
    if (array2==null) return -2;
    int length1=array1.length;
    if (length1==0) return -2;
    int length2=array2.length;
    if (length2==0) return -2;
    int minLength=length1<length2?length1:length2;
    for (int i=0; i<minLength; i++)
    { if (array1<array2[i]) return -1;
if (array1[i]>array2[i]) return 1;
return length1==length2 ? 0 : length1<length2 ? -1 : 1;
public boolean contained(char[] word)
{ int compare=compare(this.word,word);
if (compare==1&&this.precursor!=null)
return this.precursor.contained(word);
if (compare==0) return true;
if (compare==-1&&this.successor!=null)
return this.successor.contained(word);
return false;
public int listNodeCount(boolean iterative)
/* students to complete */
public int maximumWordLength(int currentLength)
/* students to complete */
public String toString()
{ String string="";
if (this.precursor!=null) string+=this.precursor;
string+="\""+(new String(this.word))+"\""+this.list;
if (this.successor!=null) string+=this.successor;
return string;
public int treeNodeCount()
/* students to complete */
public String wordArray(int length)
/* students to complete */
Edited by: allergy01 on Apr 25, 2009 9:19 PM
Edited by: allergy01 on Apr 25, 2009 9:20 PM