From 25936d8413c73b7b542c6248f4d73b1965a005e2 Mon Sep 17 00:00:00 2001
From: Julien Lengrand-Lambert <jlengrand@gmail.com>
Date: Mon, 15 Jul 2013 16:31:07 +0200
Subject: [PATCH] implements print tree method

---
 01_binary_search_trees/bst.py      | 23 +++++++++++++++++++++--
 01_binary_search_trees/bst_test.py | 26 ++++++++++++++++++++++++--
 2 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/01_binary_search_trees/bst.py b/01_binary_search_trees/bst.py
index 163475b..ed442dc 100644
--- a/01_binary_search_trees/bst.py
+++ b/01_binary_search_trees/bst.py
@@ -82,8 +82,27 @@ class BinarySearchTree():
         """
         Prints a nice version of the binary search node
         """
-        #TODO
-        return self.root_node.__str__()
+        max_iter = 1000000000  # max number of nodes
+        ite = 0
+        ret = ""
+        node = self.root_node
+
+        top = False  # dictates when to climb one level
+        while(ite < max_iter):
+            while (node.has_left_child()):
+                node = node.left_child
+                top = True
+            ret += str(node.value) + " "
+            if top:  # we need to climb one level
+                node = node.parent
+                top = False
+                ret += str(node.value) + " "
+            if (not node.has_right_child()):
+                return ret.strip()  # removes superflous spaces
+            else:
+                node = node.right_child
+            ite += 1
+        return None  # problem
 
     @staticmethod
     def is_search_tree(a_tree_root):
diff --git a/01_binary_search_trees/bst_test.py b/01_binary_search_trees/bst_test.py
index 187a814..101a8a1 100644
--- a/01_binary_search_trees/bst_test.py
+++ b/01_binary_search_trees/bst_test.py
@@ -186,7 +186,7 @@ class test_binary_search_tree(unittest.TestCase):
         self.assertEqual(bst.root_node.right_child.value, 20)
         self.assertFalse(BinarySearchTree.is_search_tree(bst.root_node))
 
-    def test_print(self):
+    def test_print_node(self):
         bst = BinarySearchTree()
 
         self.assertEqual(bst.min(), None)
@@ -206,11 +206,33 @@ class test_binary_search_tree(unittest.TestCase):
         #       \
         #        16
 
-        self.assertEqual(bst.__str__(), "4 6 10")
+        #self.assertEqual(bst.__str__(), "4 6 10")
 
+        self.assertEqual(bst.root_node.__str__(), "4 6 10")
         self.assertEqual(bst.root_node.right_child.__str__(), "10 16")
         self.assertEqual(bst.root_node.right_child.right_child.__str__(), "16")
 
+    def test_print_tree(self):
+        bst = BinarySearchTree()
+
+        self.assertEqual(bst.min(), None)
+
+        node_val1 = 6
+        bst.add(node_val1)
+        node_val2 = 4
+        bst.add(node_val2)
+        node_val3 = 10
+        bst.add(node_val3)
+        node_val4 = 16
+        bst.add(node_val4)
+
+        #    6
+        #   / \
+        #  4   10
+        #       \
+        #        16
+
+        self.assertEqual(bst.__str__(), "4 6 10 16")
 
 if __name__ == '__main__':
     unittest.main()