Non-recursive postorder traversal (bst)

Question

Hello!
I'm having difficulty writing a non-recursive postorder traversal for a binary search tree. Not getting an error via compiler but I know that the answer is incorrect. Please provide some insight on what I'm doing wrong!
Here's an example of what I mean by incorrect..
correct postorder answer (done recursively) --> 0 4 2 6 10 12 14 8 18 16
what I'm getting using the function below --> 8 6 2 0 4 14 12 10 18 18
And here's what I have:
public void nonRecursivePostorder(BinarySearchTreeNode<T> root, StringBuffer result)
LinkedStack<BinarySearchTreeNode<T>> stack = new LinkedStack<BinarySearchTreeNode<T>>();
BinarySearchTreeNode<T> currentNode = root;
boolean done;
done = (currentNode == null);
while (!done)
if (currentNode.getLeft() != null)
if (currentNode.getRight() != null)
stack.push(currentNode.getRight());
currentNode = currentNode.getLeft();
else if (currentNode.getRight() != null)
currentNode = currentNode.getRight();
else if (stack.empty())
done = true;
else
currentNode = stack.top();
stack.pop();
System.out.print(currentNode.getData() + " ");
}

Answer 1

When you post code, wrap it in code tags.
Anyway, ultimately the solution is to put in debugging tags to see where things are going wrong.
You don't really need that done variable. Just check the stack.
Though actually IIRC, you'd actually need a queue.