diff --git a/include/bus.h b/include/bus.h
index 7ae4291..beae35f 100644
--- a/include/bus.h
+++ b/include/bus.h
@@ -40,5 +40,5 @@ void UpBus(rail_node_t* rail_node);
  * @param rail_node 当前所在的站点
  */
 void DownBus(rail_node_t* rail_node);
-
+int sum(int a,int b);
 #endif //AUTO_PILOT_BUS_BUS_H
diff --git a/src/bus.c b/src/bus.c
index f47b66b..c1086c7 100644
--- a/src/bus.c
+++ b/src/bus.c
@@ -1 +1,7 @@
-#include "bus.h"
\ No newline at end of file
+#include "bus.h"
+int sum(int a,int b)
+{
+    int sum=b+a;
+    return sum;
+    
+}
\ No newline at end of file