Please help for a LinkBinaryTreeInJava

[Basanta]

I am new in this group,I don't know how far it would help me.
I tried to make a linked based binary tree following the book "data
structures and algorithms in java" By goodRich and tamassia.I did all
but I wanted to implement a function to determine whether a particular
node exists or not.All I want to implement a function boolean
exists(node n).Can anyone help??My program is as follows:-

import java.io.*;

interface Node {
Object getData();
int getID();
}

class TreeEmptyException extends Exception {
TreeEmptyException(String message) {
super(message);
}
}

class LinkBinTree {
BinNode root;
int size;
LinkBinTree(Object O) {
root = new BinNode(0);
}

class BinNode implements Node {
int id;
BinNode left;
BinNode right;
Object data;
BinNode(int iden) {
id = iden;
left = null;
right = null;
data = null;
}
BinNode(Object O) {
id = 0;
left = null;
right = null;
data = null;
}
public Object getData() {return data;}
public int getID() { return id;}


void addLeft(Object obj) {
BinNode b = new BinNode(obj);
left = b;
}

void addRight(Object obj) {
BinNode r = new BinNode(obj);
right = r;
}

BinNode addLeft(Node n,Object O) throws TreeEmptyException
{
if(!exists(n)) throw new TreeEmptyException("Tree doesn't
exists");
return n.addLeft(O);
}

BinNode addRight(Node n,Object O) throws TreeEmptyException{
if(!exists(n)) throw new TreeEmptyException("Tree doesn't
exists");
return n.addRight(O);
}

void preOrder(Node n) {
LinkQueueApp<Integer> q =new LinkQueueApp<Integer>();
int p=n.getID();
q.enqueue(p);
while(!q.isEmpty()) {
p =q.dequeue();
System.out.println("The pre-order is : "
+n.getData());
for(int i=p;(i==p+1) || (i==p+2)&&i<=size;i++)
q.enqueue(i);
}

}

void boolean exists(Node n) {
if(Node == root) return;
else {
if(Node

 

[Jussi Piitulainen]

LinkBinTree(Object O) {
root = new BinNode(0);
}

Set your font so that the letter O and the digit 0 look different.
(Same for I, l and 1, but your code happens to exhibit O and 0.)

 

[Lew]

Set your font so that the letter O and the digit 0 look different.
(Same for I, l and 1, but your code happens to exhibit O and 0.)

He doesn't set a font. His message is in 'text/plain', meaning the font
you're seeing is set in your client.

I am disappointed that the OP multiposted. There are many answers in
clj.help, for those reading clj.programmer.