10.6.1 Starting at the First Node [ToC] [Index]     [Skip Fwd]     [Prev] [Up] [Next]

To find the first (least) item in the tree, we just descend all the way to the left, as usual. In an RTBST, as in a BST, this involves checking for null pointers.

398. <RTBST traverser first initializer 398> =
void *
rtbst_t_first (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_link[0] != NULL) trav->rtbst_node = trav->rtbst_node->rtbst_link[0]; return trav->rtbst_node->rtbst_data; } else
    return NULL; }

This code is included in 397.