#include <search.h>
#include "tsearch.h"
static void walk(const struct node *r, void (*action)(const void *, VISIT, int), int d)
{
if (!r)
return;
if (r->h == 1)
action(r, leaf, d);
else {
action(r, preorder, d);
walk(r->a[0], action, d+1);
action(r, postorder, d);
walk(r->a[1], action, d+1);
action(r, endorder, d);
}
}
void twalk(const void *root, void (*action)(const void *, VISIT, int))
{
walk(root, action, 0);
}