diff --git a/include/tree.h b/include/tree.h
index 92cd635..c670151 100644
--- a/include/tree.h
+++ b/include/tree.h
@@ -124,10 +124,10 @@ struct _tree
     // ----- print -----
     // traversal depth
     void (*preorder)(struct _tree* self, struct _tree_node* root);
-    void (*inorder)(struct _tree* self);
-    void (*postorder)(struct _tree* self);
+    void (*inorder)(struct _tree* self, struct _tree_node* root);
+    void (*postorder)(struct _tree* self, struct _tree_node* root);
     // traversal breadth
-    void (*breadth)(struct _tree* self);
+    void (*breadth)(struct _tree* self, struct _tree_node* root);
 
     void (*print_obj)(void* obj);
 };
diff --git a/src/tree.c b/src/tree.c
index 1518563..54e0a1a 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -1588,29 +1588,47 @@ void tree_destory(struct _tree* self)
 void tree_avl_preorder(struct _tree* self, struct _tree_node* root)
 {
     assert(self != NULL);
+    self->print_obj(root->obj);
     if(root->left != NULL)
     {
         tree_avl_preorder(self, root->left);
     }
-    self->print_obj(root->obj);
     if(root->right != NULL)
     {
         tree_avl_preorder(self, root->right);
     }
 }
 
-void tree_avl_inorder(struct _tree* self)
+void tree_avl_inorder(struct _tree* self, struct _tree_node* root)
 {
-
+    assert(self != NULL);
+    if(root->left != NULL)
+    {
+        tree_avl_inorder(self, root->left);
+    }
+    self->print_obj(root->obj);
+    if(root->right != NULL)
+    {
+        tree_avl_inorder(self, root->right);
+    }
 }
 
-void tree_avl_postorder(struct _tree* self)
+void tree_avl_postorder(struct _tree* self, struct _tree_node* root)
 {
-
+    assert(self != NULL);
+    if(root->left != NULL)
+    {
+        tree_avl_postorder(self, root->left);
+    }
+    if(root->right != NULL)
+    {
+        tree_avl_postorder(self, root->right);
+    }
+    self->print_obj(root->obj);
 }
 
 // traversal breadth
-void tree_avl_breadth(struct _tree* self)
+void tree_avl_breadth(struct _tree* self, struct _tree_node* root)
 {
 
 }
diff --git a/test/tree_test.c b/test/tree_test.c
index 5af5fb6..2e4641b 100644
--- a/test/tree_test.c
+++ b/test/tree_test.c
@@ -270,7 +270,8 @@ void tree_test(void)
 void test_tree_num(void)
 {
     uint32_t i = 0;
-    int data[] = { 1,2,3,4,5,6,7,8,9,10 };
+    // int data[] = { 1,2,3,4,5,6,7,8,9,10 };
+    int data[] = { 5,2,3,1,7,8,6 };
     int temp = 0;
     uint32_t len = sizeof(data) / sizeof(data[0]);
 
@@ -290,6 +291,14 @@ void test_tree_num(void)
     tree->preorder(tree, tree->_root);
     printf("\n");
 
+    printf("----- inorder -----\n");
+    tree->inorder(tree, tree->_root);
+    printf("\n");
+
+    printf("----- postorder -----\n");
+    tree->postorder(tree, tree->_root);
+    printf("\n");
+
     tree_free(tree);
 }