// Remark: this is just a fragment of code, it cannot be compiled directly. 


  static void inOrder(TreeNode<T> root)
  {
    TreeNode<T> prev = null;
    TreeNode<T> current = root;
    TreeNode<T> next = null;

    while (current != null) {
    	if (prev == current.getParent())
    	{
    		prev = current;
    		next = current.getLeft();
    	}
    	
    	if (next == null || prev == current.getLeft())
    	{
    		visit(current);
    		prev = current;
    		next = cuurent.getRight();
    	}
    	
    	if (next == null || prev == current.getRight())
    	{
    		prev = current;
    		next = cuurent.getParent();
    	}
    	
    	current = next;
    } // end while 
  }	// end inOrder