diff --git a/y2020/vision/sift/sift971.cc b/y2020/vision/sift/sift971.cc
index 93d71e4..788ae23 100644
--- a/y2020/vision/sift/sift971.cc
+++ b/y2020/vision/sift/sift971.cc
@@ -106,13 +106,13 @@
 
 #include "y2020/vision/sift/sift971.h"
 
+#include <cstdarg>
 #include <iostream>
 #include <mutex>
-#include <stdarg.h>
 #include <opencv2/core/hal/hal.hpp>
 #include <opencv2/imgproc.hpp>
-#include "glog/logging.h"
 
+#include "glog/logging.h"
 #include "y2020/vision/sift/fast_gaussian.h"
 
 using namespace cv;