Basanta wrote:
> 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:-
>
> im****t java.io.*;
>
> interface Node {
> Object getData();
> int getID();
> }
A generic approach (as a matter of style I include the redundant 'public'
in
interface declarations):
interface Node <T>
{
T getData();
Integer getId(); // could parameterize ID type
}
> class LinkBinTree {
> BinNode root;
> int size;
> LinkBinTree(Object O) {
> root = new BinNode(0);
> }
Avoid exorbitant indentation. Up to four spaces per level will suffice.
class BinNode <T> implements Node <T>
> {
T data;
Integer id;
> BinNode left;
> BinNode right;
public BinNode( Integer iden )
> {
> id = iden;
> left = null;
> right = null;
> data = null;
You don't need to set things to null again.
}
> BinNode(Object O) {
Why do you have this constructor?
Parameters should have names that start with a lower-case letter: 'o', not
'O'.
> id = 0;
> left = null;
> right = null;
> data = null;
You don't need to set things to null or zero again.
> }
public T getData() {return data;}
> public int getID() { return id;}
>
>
> void addLeft( T obj ) {
> BinNode b = new BinNode(obj);
> left = b;
You don't need 'b':
left = new BinNode( obj );
> }
>
> void addRight( T obj ) {
> BinNode r = new BinNode(obj);
> right = r;
> }
>
public
> BinNode <T> addLeft(Node <T> n, T o ) // lower-case 'o'!
throws TreeEmptyException
> {
> if(!exists(n))
// braces please:
{
throw new TreeEmptyException("Tree doesn't
> exists");
//"Tree doesn't exist"
}
> return n.addLeft( o );
> }
>
public
> BinNode <T> addRight( Node <T> n, T 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 <T> n ) {
> if(Node == root) return;
You don't show a variable 'root'.
> else {
> if(Node
>
Are you searching for a certain Node, or a Node with a certain value?
public static void boolean exists( BinNode <T> root, T value )
{
if ( root == null )
{ return false; }
return (root.value == null? value == null : root.value.equals( value ))
|| exists( root.left, value ) || exists( root.right, value );
}
--
Lew
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