#include <stdlib.h>
#include <stdio.h>
#include "bin-trees.h"

static void
real_in_order_traverse_no_recurse (tree_ptr root)
{
  struct stack_struct *stack = NULL;
  tree_ptr current= root;
  int going_left = 1;   /* boolean variable */
  while (current != NULL)
  {
    if ((current->left != NULL) && going_left)
    {
      push (&stack, current);
      current = current->left;
    }

    printf ("%d ", current->data);
    if (current->right)
    {
      current = current->right;
      going_left = 1;
    }
    else if (stack != NULL)
    {
      current = pop(&stack);
      going_left = 0;
    }
    else
      current = NULL;
  }
}

void
in_order_traverse_no_recurse (tree_ptr root)
{
  printf ("in-order traversal, without recursion: \n");
  real_in_order_traverse_no_recurse (root);
  printf ("\n");
  return;
}