diff --git a/.vscode/settings.json b/.vscode/settings.json
index 23e73d7..0df7e95 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -29,6 +29,7 @@
         "iterator.h": "c",
         "assert.h": "c",
         "limits.h": "c",
-        "cstdint": "c"
+        "cstdint": "c",
+        "unicstl_internal.h": "c"
     }
 }
\ No newline at end of file
diff --git a/demo/demo.c b/demo/demo.c
index 74af719..8fd720f 100644
--- a/demo/demo.c
+++ b/demo/demo.c
@@ -64,6 +64,7 @@ int main()
         demo_deque();
         demo_tree();
         demo_heap();
+        demo_graph();
     }
 
     printf("----- unicstl ok -----\n");
diff --git a/demo/demo.h b/demo/demo.h
index 7001b9a..36db592 100644
--- a/demo/demo.h
+++ b/demo/demo.h
@@ -45,6 +45,7 @@ void demo_deque(void);
 void demo_queue(void);
 void demo_tree(void);
 void demo_heap(void);
+void demo_graph(void);
 
 #endif // _DEMO_H_
 
diff --git a/demo/demo_graph.c b/demo/demo_graph.c
new file mode 100644
index 0000000..fd0e26d
--- /dev/null
+++ b/demo/demo_graph.c
@@ -0,0 +1,67 @@
+/**
+ * @file demo_graph.c
+ * @author wenjf (Orig5826@163.com)
+ * @brief 
+ * @version 0.1
+ * @date 2025-04-30
+ * 
+ * @copyright Copyright (c) 2025
+ * 
+ */
+#include "demo.h"
+ 
+void demo_graph_add_vertex(void)
+{
+    const int size = 10;
+    int data[10] = {
+        0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
+    };
+    int temp = 11;
+    uint32_t i = 0;
+
+    graph_t graph = graph_new(sizeof(int));
+    graph->compare = compare_num;
+    graph->print_obj = print_num;
+
+    // test add_vertex
+    for(i = 0; i < size; i++)
+    {
+        graph->add_vertex(graph, &data[i]);
+    }
+    // graph->print(graph);
+
+    // test add_edge
+    graph->add_edge(graph, &data[0], &data[1], 12);
+    graph->add_edge(graph, &data[0], &data[2], 13);
+    graph->add_edge(graph, &data[1], &data[3], 24);
+    graph->add_edge(graph, &data[5], &data[6], 67);
+    graph->add_edge(graph, &data[7], &data[6], 87);
+    graph->add_edge(graph, &data[8], &data[2], 92);
+
+    graph->add_edge(graph, &temp, &data[1], 0);
+    graph->print(graph);
+
+    iterator_t iter_vertex = NULL;
+    iter_vertex = graph->iter(graph, GRAPH_BFS, &data[0]);
+    while(iter_vertex->hasnext(iter_vertex))
+    {
+        temp = *(int *)iter_vertex->next(iter_vertex);
+        graph->print_obj(&temp);
+    }
+    printf("\n");
+
+    iter_vertex = graph->iter(graph, GRAPH_DFS, &data[0]);
+    while(iter_vertex->hasnext(iter_vertex))
+    {
+        temp = *(int *)iter_vertex->next(iter_vertex);
+        graph->print_obj(&temp);
+    }
+    printf("\n");
+
+    graph_free(&graph);
+}
+
+void demo_graph(void)
+{
+    demo_graph_add_vertex();
+}
\ No newline at end of file
diff --git a/include/deque.h b/include/deque.h
index 68a88dd..5bd53ff 100644
--- a/include/deque.h
+++ b/include/deque.h
@@ -11,7 +11,7 @@
 #ifndef _DEQUE_H_
 #define _DEQUE_H_
 
-#include "common.h"
+#include "unicstl_internal.h"
 
 enum _deque_order
 {
diff --git a/include/graph.h b/include/graph.h
index 34a41d9..739af8b 100644
--- a/include/graph.h
+++ b/include/graph.h
@@ -11,7 +11,7 @@
 #ifndef _GRAPH_H
 #define _GRAPH_H
 
-#include "common.h"
+#include "unicstl_internal.h"
 
 #include "stack.h"
 #include "queue.h"
diff --git a/include/heap.h b/include/heap.h
index d0c0d75..a68b602 100644
--- a/include/heap.h
+++ b/include/heap.h
@@ -11,7 +11,7 @@
 #ifndef _HEAP_H_
 #define _HEAP_H_
 
-#include "common.h"
+#include "unicstl_internal.h"
 
 typedef enum
 {
diff --git a/include/iterator.h b/include/iterator.h
index 5a2c153..4c5554d 100644
--- a/include/iterator.h
+++ b/include/iterator.h
@@ -11,7 +11,7 @@
 #ifndef _ITER_H_
 #define _ITER_H_
 
-#include "common.h"
+#include "unicstl_internal.h"
 
 struct _iterator
 {
diff --git a/include/list.h b/include/list.h
index 7b13a81..b62a22a 100644
--- a/include/list.h
+++ b/include/list.h
@@ -15,7 +15,7 @@
 #ifndef _LIST_H_
 #define _LIST_H_
 
-#include "common.h"
+#include "unicstl_internal.h"
 #include "iterator.h"
 
 #define LIST_UNLIMITED  INT32_MAX
diff --git a/include/queue.h b/include/queue.h
index c6a7ab2..34f04f4 100644
--- a/include/queue.h
+++ b/include/queue.h
@@ -11,7 +11,7 @@
 #ifndef _QUEUE_H_
 #define _QUEUE_H_
 
-#include "common.h"
+#include "unicstl_internal.h"
 
 struct _queue_node
 {
diff --git a/include/stack.h b/include/stack.h
index 741745b..236e618 100644
--- a/include/stack.h
+++ b/include/stack.h
@@ -11,7 +11,7 @@
 #ifndef _STACK_H_
 #define _STACK_H_
 
-#include "common.h"
+#include "unicstl_internal.h"
 
 struct _stack_node
 {
diff --git a/include/tree.h b/include/tree.h
index 5558b4c..7353187 100644
--- a/include/tree.h
+++ b/include/tree.h
@@ -11,7 +11,7 @@
 #ifndef _TREE_H_
 #define _TREE_H_
 
-#include "common.h"
+#include "unicstl_internal.h"
 
 #include "stack.h"
 #include "queue.h"
diff --git a/include/unicstl.h b/include/unicstl.h
index 06119a4..8fe81e4 100644
--- a/include/unicstl.h
+++ b/include/unicstl.h
@@ -16,7 +16,7 @@
 #define UNICSTL_VERSION_MICRO    2
 #define UNICSTL_VERSION          ((UNICSTL_VERSION_MAJOR << 16) | (UNICSTL_VERSION_MINOR << 8) | UNICSTL_VERSION_MICRO)
 
-#include "common.h"
+#include "unicstl_internal.h"
 
 #include "list.h"
 #include "stack.h"
diff --git a/include/common.h b/include/unicstl_internal.h
similarity index 89%
rename from include/common.h
rename to include/unicstl_internal.h
index 6bf1b89..fc33722 100644
--- a/include/common.h
+++ b/include/unicstl_internal.h
@@ -1,11 +1,11 @@
 /**
- * @file common.h
+ * @file unicstl_internal.h
  * @author wenjf (Orig5826@163.com)
  * @brief 
  * @version 0.1
- * @date 2024-07-03
+ * @date 2025-04-30
  * 
- * @copyright Copyright (c) 2024
+ * @copyright Copyright (c) 2025
  * 
  */
 #ifndef _COMMON_H_
diff --git a/src/deque.c b/src/deque.c
index 655d908..339365a 100644
--- a/src/deque.c
+++ b/src/deque.c
@@ -341,6 +341,9 @@ static bool deque_init(struct _deque* self, uint32_t obj_size)
     // iter
     self->iter = deque_iter;
 
+    // -------------------- default --------------------
+    self->print_obj = default_print_obj;
+
     // -------------------- debug -------------------- 
     self->print = deque_print;
     
diff --git a/src/graph.c b/src/graph.c
index 5bd349f..86ea38b 100644
--- a/src/graph.c
+++ b/src/graph.c
@@ -1056,10 +1056,11 @@ static bool graph_init(struct _graph *self, uint32_t obj_size)
     // others
     self->from_matrix = NULL;
 
+    // -------------------- default --------------------
+    self->compare = default_compare;
+    self->print_obj = default_print_obj;
 
-    self->compare = NULL;
     // -------------------- debug --------------------
-    self->print_obj = NULL;
     self->print = graph_print;
 
     return true;
diff --git a/src/heap.c b/src/heap.c
index 72531a5..b4ecbc6 100644
--- a/src/heap.c
+++ b/src/heap.c
@@ -326,6 +326,10 @@ static bool heap_init2(struct _heap* self, uint32_t obj_size, uint32_t capacity)
     // config
     self->compare = NULL;
     
+    // -------------------- default --------------------
+    self->compare = default_compare;
+    self->print_obj = default_print_obj;
+
     // -------------------- debug -------------------- 
     self->print = heap_print;
     return true;
diff --git a/src/list.c b/src/list.c
index ab4b0d6..995f518 100644
--- a/src/list.c
+++ b/src/list.c
@@ -364,63 +364,64 @@ iterator_t list_iter(struct _list* self)
     return iter;
 }
 
-static bool list_init2(struct _list* list, uint32_t obj_size, uint32_t capacity)
+static bool list_init2(struct _list* self, uint32_t obj_size, uint32_t capacity)
 {
-    assert(list != NULL);
-    if (list == NULL || obj_size == 0 || capacity == 0)
+    assert(self != NULL);
+    if (self == NULL || obj_size == 0 || capacity == 0)
     {
         return false;
     }
 
     // -------------------- private -------------------- 
-    list->_obj_size = obj_size;
-    list->_size = 0;
-    list->_capacity = capacity;
-    list->_ratio = 2;
-    list->_cur = 0;
+    self->_obj_size = obj_size;
+    self->_size = 0;
+    self->_capacity = capacity;
+    self->_ratio = 2;
+    self->_cur = 0;
 
-    list->obj = (void*)malloc(list->_capacity * list->_obj_size);
-    if (list->obj == NULL)
+    self->obj = (void*)malloc(self->_capacity * self->_obj_size);
+    if (self->obj == NULL)
     {
         return false;
     }
 
-    list->_iter.next = list_iter_next;
-    list->_iter.hasnext = list_iter_hasnext;
+    self->_iter.next = list_iter_next;
+    self->_iter.hasnext = list_iter_hasnext;
 
-    list->_destory = list_destory;
+    self->_destory = list_destory;
 
     // -------------------- public -------------------- 
     // kernel
-    list->append = list_append;
-    list->pop = list_pop;
+    self->append = list_append;
+    self->pop = list_pop;
 
-    list->insert = list_insert;
-    list->delete = list_delete;
+    self->insert = list_insert;
+    self->delete = list_delete;
 
-    list->get = list_get;
-    list->set = list_set;
+    self->get = list_get;
+    self->set = list_set;
 
-    list->index = list_index;
-    // list->contains = list_contains;
+    self->index = list_index;
+    // self->contains = list_contains;
 
     // base
-    list->clear = list_clear;
-    list->size = list_size;
-    list->empty = list_empty;
-    list->capacity = list_capacity;
+    self->clear = list_clear;
+    self->size = list_size;
+    self->empty = list_empty;
+    self->capacity = list_capacity;
 
     // iter
-    list->iter = list_iter;
+    self->iter = list_iter;
 
     // others
-    list->slice = list_slice;
+    self->slice = list_slice;
+
+    // -------------------- default --------------------
+    self->compare = default_compare;
+    self->print_obj = default_print_obj;
 
-    // config
-    list->compare = default_compare;
     // -------------------- debug --------------------
-    list->print_obj = default_print_obj;
-    list->print = list_print;
+    self->print = list_print;
 
     return true;
 }
diff --git a/src/queue.c b/src/queue.c
index bbe91d3..a1fe3c0 100644
--- a/src/queue.c
+++ b/src/queue.c
@@ -420,6 +420,9 @@ static bool queue_init(struct _queue * self, uint32_t obj_size)
     // iter
     self->iter = queue_iter;
 
+    // -------------------- default --------------------
+    self->print_obj = default_print_obj;
+
     // -------------------- debug -------------------- 
     self->print = queue_print;
     
@@ -483,6 +486,9 @@ static bool queue_init2(struct _queue * self, uint32_t obj_size, uint32_t capaci
     // iter
     self->iter = queue2_iter;
 
+    // -------------------- default --------------------
+    self->print_obj = default_print_obj;
+    
     // -------------------- debug -------------------- 
     self->print = queue2_print;
 
diff --git a/src/stack.c b/src/stack.c
index f21bd14..f700da7 100644
--- a/src/stack.c
+++ b/src/stack.c
@@ -323,7 +323,7 @@ static bool stack_init(struct _stack* self, uint32_t obj_size)
         return false;
     }
 
-    // ---------- private ----------
+    // -------------------- private --------------------
     self->_obj_size = obj_size;
     self->_size = 0;
     self->_capacity = UINT32_MAX;
@@ -339,7 +339,7 @@ static bool stack_init(struct _stack* self, uint32_t obj_size)
 
     self->_destory = stack_destory;
 
-    // ---------- public ----------
+    // -------------------- public --------------------
     // kernel
     self->push = stack_push;
     self->pop = stack_pop;
@@ -354,8 +354,12 @@ static bool stack_init(struct _stack* self, uint32_t obj_size)
     // iter
     self->iter = stack_iter;
     
-    // ---------- debug ----------
+    // -------------------- default --------------------
+    self->print_obj = default_print_obj;
+    
+    // -------------------- debug --------------------
     self->print = stack_print;
+
     return true;
 }
 
@@ -367,7 +371,7 @@ static bool stack_init2(struct _stack* self, uint32_t obj_size, uint32_t capacit
         return false;
     }
 
-    // ---------- private ----------
+    // -------------------- private --------------------
     self->_obj_size = obj_size;
     self->_size = 0;
     self->_capacity = capacity;
@@ -393,7 +397,7 @@ static bool stack_init2(struct _stack* self, uint32_t obj_size, uint32_t capacit
 
     self->_destory = stack2_destory;
 
-    // ---------- public ----------
+    // -------------------- public --------------------
     // kernel
     self->push = stack2_push;
     self->pop = stack2_pop;
@@ -408,8 +412,12 @@ static bool stack_init2(struct _stack* self, uint32_t obj_size, uint32_t capacit
     // iter
     self->iter = stack_iter;
 
-    // ---------- debug ----------
+    // -------------------- default --------------------
+    self->print_obj = default_print_obj;
+
+    // -------------------- debug --------------------
     self->print = stack2_print;
+
     return true;
 }
 
diff --git a/src/tree.c b/src/tree.c
index 9b75030..9691fcf 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -1420,6 +1420,10 @@ static bool tree_avl_init(struct _tree* self, uint32_t obj_size)
     // others
     self->max = tree_max;
     self->min = tree_min;
+    
+    // -------------------- default --------------------
+    self->compare = default_compare;
+    self->print_obj = default_print_obj;
 
     return true;
 }
@@ -1469,6 +1473,10 @@ static bool tree_rb_init(struct _tree* self, uint32_t obj_size)
     self->max = tree_max;
     self->min = tree_min;
 
+    // -------------------- default --------------------
+    self->compare = default_compare;
+    self->print_obj = default_print_obj;
+
     return true;
 }
 
diff --git a/src/unicstl_internal.c b/src/unicstl_internal.c
index e502dfc..8c271a6 100644
--- a/src/unicstl_internal.c
+++ b/src/unicstl_internal.c
@@ -8,7 +8,7 @@
  * @copyright Copyright (c) 2025
  * 
  */
-#include "common.h"
+#include "unicstl_internal.h"
 
 int default_compare(void* obj1, void* obj2)
 {