diff --git a/constants/constants.h b/constants/constants.h
index 7a31750..e72dd64 100644
--- a/constants/constants.h
+++ b/constants/constants.h
@@ -3,6 +3,7 @@
 
 #include <QtCore>
 #include <include/vssref_common.pb.h>
+#include <iostream>
 
 class Constants
 {