diff --git a/rt-thread-version/rt-thread-standard/tutorial/beep-player/pin.md b/rt-thread-version/rt-thread-standard/tutorial/beep-player/pin.md
index 62c1b0394cd46f9c3d03d5c925bdc5088dba0dda..79b779cd5b24d1fb94c29e8a3c8fef0fe516d6ce 100644
--- a/rt-thread-version/rt-thread-standard/tutorial/beep-player/pin.md
+++ b/rt-thread-version/rt-thread-standard/tutorial/beep-player/pin.md
@@ -127,7 +127,7 @@ int led_off(void)
 int led_toggle(void);        //LED 灯亮灭状态翻转
 ```
 
-要使 LED 状态翻转应先利用API  `rt_pin_read` 读出当前电平，然后输出相反电平 
+要使 LED 状态翻转应先利用API  `rt_pin_read` 读出当前电平，然后输出相反电平。
 
 ```c
 int led_toggle(void)
@@ -158,6 +158,8 @@ int main(void)
         led_toggle();
         rt_thread_mdelay(500);
     }
+
+    return 0;
 }
 ```