1 files changed, 5 insertions, 2 deletions
diff --git a/list.c b/list.c
index c204bce..e4c425b 100644
--- a/list.c
+++ b/list.c
@@ -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.c--支持列表操作的函数
 #include <stdio.h>