inOrderTraverse implemented

@cs/BinaryTree.php

@@ -76,11 +76,15 @@ private function searchNode($node, $key) {
     }
 
     public function inOrderTraverse(\Closure $callback) {
-
+        $this->inOrderTraverseNode($this->root, $callback);
     }
 
     private function inOrderTraverseNode($node, $callback) {
-
+        if($node !== null) {
+            $this->inOrderTraverseNode($node->left, $callback);
+            $callback($node->key);
+            $this->inOrderTraverseNode($node->right, $callback);
+        }
     }
 
     public function preOrderTraverse(\Closure $callback) {
@@ -99,4 +103,31 @@ private function postOrderTraverseNode($node, $callback) {
 
     }
 
+    /**
+     * Get the key with the lowest value
+     *
+     * @param $key
+     */
+    public function min($key) {
+
+    }
+
+    /**
+     * Get the key w/the highest value
+     *
+     * @param $key
+     */
+    public function max($key) {
+
+    }
+
+    /**
+     * Remove a node via its' key
+     *
+     * @param $key
+     */
+    public function remove($key) {
+
+    }
+
 } // END OF: class BinarySearchTree

@cs/index.php

@@ -18,7 +18,15 @@
     $binaryTree->insert($v);
 }
 
+echo "\n----------------------------------------------------------------------\n";
 
+$callback = function($value){
+    echo " [$value] ";
+};
+
+$binaryTree->inOrderTraverse($callback);
+
+echo "\n----------------------------------------------------------------------\n";