diff --git a/.vscode/settings.json b/.vscode/settings.json
index 85ec3df..1ee84b4 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -25,6 +25,7 @@
         "stdarg.h": "c",
         "graph.h": "c",
         "unicstl_config.h": "c",
-        "iter.h": "c"
+        "iter.h": "c",
+        "iterator.h": "c"
     }
 }
\ No newline at end of file
diff --git a/include/iter.h b/include/iterator.h
similarity index 62%
rename from include/iter.h
rename to include/iterator.h
index 85c86d5..a3c7729 100644
--- a/include/iter.h
+++ b/include/iterator.h
@@ -15,17 +15,11 @@
 
 struct _iterator
 {
-    void* obj;
-    void* self;
     void* parent;
-
-    void* (*begin)(struct _iterator* self);
-    void* (*next)(struct _iterator* self);
-    void* (*end)(struct _iterator* self);
+    uint32_t _cur;
 
     bool (*hasnext)(struct _iterator* self);
-
-    void* (*data)(struct _iterator* self);
+    const void* (*next)(struct _iterator* self);
 };
 typedef struct _iterator* iterator_t;
 
diff --git a/include/list.h b/include/list.h
index f1171b5..4c5eef7 100644
--- a/include/list.h
+++ b/include/list.h
@@ -12,7 +12,7 @@
 #define _LIST_H_
 
 #include "common.h"
-#include "iter.h"
+#include "iterator.h"
 
 struct _list
 {
diff --git a/src/list.c b/src/list.c
index 6198f0e..d3fcd4b 100644
--- a/src/list.c
+++ b/src/list.c
@@ -250,55 +250,33 @@ static bool list_init2(struct _list* list, uint32_t obj_size, uint32_t capacity)
     return true;
 }
 
-iterator_t list_iter(struct _list* self)
-{
-    self->_cur = 0;
-    self->_iter.obj = self->obj;
-    return &self->_iter;
-}
-
-static void* list_iter_begin(struct _iterator* iter)
+static const void* list_iter_next(struct _iterator* iter)
 {
     list_t self = (list_t)iter->parent;
-    self->_cur = 0;
-    iter->obj = self->obj;
-    return iter;
-}
-
-static void* list_iter_end(struct _iterator* iter)
-{
-    list_t self = (list_t)iter->parent;
-    iter->obj = (char*)self->obj + self->_size * self->_obj_size;
-    return iter;
-}
-
-static void* list_iter_next(struct _iterator* iter)
-{
-    list_t self = (list_t)iter->parent;
-
-    // if add this, can't go to end
-    // if(self->_cur < self->_size - 1)
-    {
-        self->_cur += 1;
-    }
-    iter->obj = (char*)self->obj + self->_cur * self->_obj_size;
-    return iter;
+    void *obj = self->obj + self->_iter._cur * self->_obj_size;
+    self->_iter._cur += 1;
+    return obj;
 }
 
 static bool list_iter_hasnext(struct _iterator* iter)
 {
     list_t self = (list_t)iter->parent;
 
-    if(self->_cur < self->_size)
+    if(self->_iter._cur < self->size(self))
     {
         return true;
     }
     return false;
 }
 
-static void* list_iter_data(struct _iterator* iter)
+iterator_t list_iter(struct _list* self)
 {
-    return iter->obj;
+    self->_iter.parent = self;
+    self->_iter._cur = 0;
+
+    self->_iter.next = list_iter_next;
+    self->_iter.hasnext = list_iter_hasnext;
+    return &self->_iter;
 }
 
 list_t list_new2(uint32_t obj_size, uint32_t capacity)
@@ -315,15 +293,6 @@ list_t list_new2(uint32_t obj_size, uint32_t capacity)
         }
     }
 
-    list->_iter.self = &list->iter;
-    list->_iter.parent = list;
-
-    list->_iter.begin = list_iter_begin;
-    list->_iter.next = list_iter_next;
-    list->_iter.end = list_iter_end;
-    list->_iter.data = list_iter_data;
-    list->_iter.hasnext = list_iter_hasnext;
-
     list->iter = list_iter;
     return list;
 }
diff --git a/test/test_list.c b/test/test_list.c
index 4c2d29f..58e1170 100644
--- a/test/test_list.c
+++ b/test/test_list.c
@@ -353,19 +353,16 @@ void list_iter_test(void)
         TEST_ASSERT_FALSE(list->empty(list));
     }
 
-    iterator_t it = list->iter(list);
-    printf("iter start\n");
-    list->print(list);
-
-    printf("\n");
-    while(it->hasnext(it))
+    iterator_t iter = list->iter(list);
+    int iter_data = 0;
+    int idx = 0;
+    while(iter->hasnext(iter))
     {
-        int dd = *(int*)it->data(it);
-        printf("%d ", dd);
-        it->next(it);
+        iter_data = *(int*)iter->next(iter);
+        // printf("%d ", dd);
+        TEST_ASSERT_EQUAL_INT(data[idx], iter_data);
+        idx++;
     }
-    printf("\niter end\n");
-
     list_free(&list);
 }