fix url of protect-re.cpp
diff --git a/readme.md b/readme.md
index cb34add..ce8ebc0 100644
--- a/readme.md
+++ b/readme.md
@@ -366,7 +366,7 @@
 
 ```
 Call `readyRE()` instead of `ready()` when using `AutoGrow` mode.
-See [test/protect-re.cpp](test/protect-re.cpp).
+See [protect-re.cpp](sample/protect-re.cpp).
 
 ## Macro