10.6.2 Starting at the Last Node

To start at the last (greatest) item in the tree, we descend all the way to the right. In an RTBST, as in a TBST, this involves checking for thread links.

399. <RTBST traverser last initializer 399> =
void *
rtbst_t_last (struct rtbst_traverser *trav, struct rtbst_table *tree) 
{
  assert (tree != NULL && trav != NULL);

  trav->rtbst_table = tree;
  trav->rtbst_node = tree->rtbst_root;
  if (trav->rtbst_node != NULL) 
    {
      while (trav->rtbst_node->rtbst_rtag == RTBST_CHILD)
        trav->rtbst_node = trav->rtbst_node->rtbst_link[1];
      return trav->rtbst_node->rtbst_data;
    }
  else 
    return NULL;
}

This code is included in 397.