public void add (int val)
    {
	binaryTreeNode tmp;
	boolean done = false;

	if (null == root)
	{
	    root = new binaryTreeNode (val);
	}
	else
	{
	    tmp = root;
	    while (!done)
	    {
		if (val < tmp.getValue ())
		{
		    if (null == tmp.getLeftChild ())
		    {
			tmp.setLeftChild (new binaryTreeNode (val));
			done = true;
		    }
		    else
		    {
			tmp = tmp.getLeftChild ();
		    }
		}
		else // the new value >= value at tmp
		{
		    if (null == tmp.getRightChild ())
		    {
			tmp.setRightChild (new binaryTreeNode (val));
			done = true;
		    }
		    else
		    {
			tmp = tmp.getRightChild ();
		    }
		}
	    }
	}
    }