1 files changed, 5 insertions, 2 deletions
diff --git a/list.h b/list.h
index d5aef17..f83471d 100644
--- a/list.h
+++ b/list.h
@@ -1,5 +1,8 @@
-// references:
-// edited from "C Primer Plus" Chapter17 practice problem 2
+// list.c and list.h contain source code I edited from book "C Primer Plus"
+// Chapter17 practice problem 2 which contain codes from its example codes, and
+// the author of "C Primer Plus" does not have a license for list.c and list.h,
+// so the author of "C Primer Plus" has the copyright on list.c and list.h, so
+// list.c and list.h can be considered non-free close souce proprietary code.
 
 /*list.h--简单列表类型的头文件*/
 #ifndef LIST_H_