/**
* Traverses a tree breadth-first, printing each node as it is visited.
* Uses a queue to keep track of the nodes to be visited.
*
* @param object ITree $tree The tree to traverse.
*/
public static function breadthFirstTraversal(ITree $tree)
{
$queue = new QueueAsLinkedList();
if (!$tree->isEmpty()) {
$queue->enqueue($tree);
}
while (!$queue->isEmpty()) {
$t = $queue->dequeue();
printf("%s\n", str($t->getKey()));
for ($i = 0; $i < $t->getDegree(); ++$i) {
$subTree = $t->getSubtree($i);
if (!$subTree->isEmpty()) {
$queue->enqueue($subTree);
}
}
}
}
/**
* Tree test program.
*
* param tree The tree to test.
*/
public static function test(ITree $tree)
{
printf("AbstractTree test program.\n");
printf("Breadth-First traversal\n");
$tree->breadthFirstTraversal(new PrintingVisitor(STDOUT));
printf("Preorder traversal\n");
$tree->depthFirstTraversal(new PreOrder(new PrintingVisitor(STDOUT)));
printf("Inorder traversal\n");
$tree->depthFirstTraversal(new InOrder(new PrintingVisitor(STDOUT)));
printf("Postorder traversal\n");
$tree->depthFirstTraversal(new PostOrder(new PrintingVisitor(STDOUT)));
printf("Using foreach\n");
foreach ($tree as $obj) {
printf("%s\n", str($obj));
}
printf("Using reduce\n");
$tree->reduce(create_function('$sum,$obj', 'printf("%s\\n", str($obj));'), '');
printf("Using accept\n");
$tree->accept(new ReducingVisitor(create_function('$sum,$obj', 'printf("%s\\n", str($obj));'), ''));
}
