diff --git a/src/tree.c b/src/tree.c
index 1ddc1b7..d58610b 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -1485,6 +1485,7 @@ void* tree_begin(struct _tree* self)
     {
         struct _tree_node* node = NULL;
         self->cur_node = self->_root;
+        self->stack->clear(self->stack);
 
         while(!self->stack->empty(self->stack) || self->cur_node != NULL)
         {
@@ -1513,6 +1514,7 @@ void* tree_begin(struct _tree* self)
     {
         struct _tree_node* node = NULL;
         self->cur_node = self->_root;
+        self->stack->clear(self->stack);
 
         while(!self->stack->empty(self->stack) || self->cur_node != NULL)
         {
@@ -1539,6 +1541,8 @@ void* tree_begin(struct _tree* self)
     case ORDER_LEFT_POST:
     {
         struct _tree_node* node = self->_root;
+        self->stack->clear(self->stack);
+
         stack_t stack = stack_new();
         stack_init(stack, sizeof(struct _tree_node*));
         while(!stack->empty(stack) || node != NULL)
@@ -1569,6 +1573,7 @@ void* tree_begin(struct _tree* self)
         return self->cur_node == NULL ? NULL : self->cur_node->obj;
     }break;
     case ORDER_LEFT_BREADTH:
+    case ORDER_RIGHT_BREADTH:
     {
         struct _tree_node* node = self->_root;
         self->queue->clear(self->queue);
@@ -1577,22 +1582,38 @@ void* tree_begin(struct _tree* self)
         if(node != NULL)
         {
             queue->push(queue, &node);
-            while(!queue->empty(queue))
+            if(!queue->empty(queue))
             {
                 queue->pop(queue, &node);
-                if(node->left != NULL)
+                if(self->_order == ORDER_LEFT_BREADTH)
                 {
-                    queue->push(queue, &node->left);
+                    if(node->left != NULL)
+                    {
+                        queue->push(queue, &node->left);
+                    }
+                    if(node->right != NULL)
+                    {
+                        queue->push(queue, &node->right);
+                    }
                 }
-                if(node->right != NULL)
+                else
                 {
-                    queue->push(queue, &node->right);
+                    if(node->right != NULL)
+                    {
+                        queue->push(queue, &node->right);
+                    }
+                    if(node->left != NULL)
+                    {
+                        queue->push(queue, &node->left);
+                    }
                 }
-                // self->print_obj(node->obj);
-                break;
+                self->cur_node = node;
+            }
+            else
+            {
+                self->cur_node = NULL;
             }
         }
-        self->cur_node = node;
         return self->cur_node == NULL ? NULL : self->cur_node->obj;
     }break;
     case ORDER_RIGHT_PRE:
@@ -1606,10 +1627,6 @@ void* tree_begin(struct _tree* self)
     case ORDER_RIGHT_POST:
     {
 
-    }break;
-    case ORDER_RIGHT_BREADTH:
-    {
-
     }break;
     default:
     {
@@ -1686,21 +1703,35 @@ void* tree_next(struct _tree* self)
         return self->cur_node == NULL ? NULL : self->cur_node->obj;
     }break;
     case ORDER_LEFT_BREADTH:
+    case ORDER_RIGHT_BREADTH:
     {
         struct _tree_node* node = self->cur_node;
         queue_t queue = self->queue;
         if(!queue->empty(queue) && node != NULL)
         {
             queue->pop(queue, &node);
-            if(node->left != NULL)
+            if(self->_order == ORDER_LEFT_BREADTH)
             {
-                queue->push(queue, &node->left);
+                if(node->left != NULL)
+                {
+                    queue->push(queue, &node->left);
+                }
+                if(node->right != NULL)
+                {
+                    queue->push(queue, &node->right);
+                }
             }
-            if(node->right != NULL)
+            else
             {
-                queue->push(queue, &node->right);
+                if(node->right != NULL)
+                {
+                    queue->push(queue, &node->right);
+                }
+                if(node->left != NULL)
+                {
+                    queue->push(queue, &node->left);
+                }
             }
-
             self->cur_node = node;
         }
         else
@@ -1720,10 +1751,6 @@ void* tree_next(struct _tree* self)
     case ORDER_RIGHT_POST:
     {
 
-    }break;
-    case ORDER_RIGHT_BREADTH:
-    {
-
     }break;
     default:
     {
diff --git a/test/test_tree.c b/test/test_tree.c
index 70af1e7..edf6c61 100644
--- a/test/test_tree.c
+++ b/test/test_tree.c
@@ -545,7 +545,7 @@ static void test_tree_iter(void)
         TEST_ASSERT_EQUAL_INT_ARRAY(expected_int_array_orderpre_insert[i], buff, count);
     }
 
-    for(i = 1; i < 3; i++)
+    for(i = 1; i < 5; i++)
     {
         tree->set_order(tree, i);  //ORDER_LEFT_IN
         // printf("\n ----- iter test -----\n");
@@ -566,7 +566,8 @@ static void test_tree_iter(void)
     // tree->set_order(tree, ORDER_LEFT_PRE);
     // tree->set_order(tree, ORDER_LEFT_IN);
     // tree->set_order(tree, ORDER_LEFT_POST);
-    tree->set_order(tree, ORDER_LEFT_BREADTH);
+    // tree->set_order(tree, ORDER_LEFT_BREADTH);
+    tree->set_order(tree, ORDER_RIGHT_BREADTH);
     printf("\n ----- iter data -----\n");
     for (count = 0, iter = tree->begin(tree); iter != tree->end(tree); iter = tree->next(tree))
     {
@@ -574,7 +575,7 @@ static void test_tree_iter(void)
         buff[count++] = *iter;
     }
     printf("\n");
-    TEST_ASSERT_EQUAL_INT_ARRAY(expected_int_array[4], buff, count);
+    TEST_ASSERT_EQUAL_INT_ARRAY(expected_int_array[tree->_order], buff, count);
 
     TEST_ASSERT_FALSE(tree->empty(tree));
     TEST_ASSERT_TRUE(tree->clear(tree));