diff --git a/sapfor/experts/Sapfor_2017/_src/Transformations/checkpoints.cpp b/sapfor/experts/Sapfor_2017/_src/Transformations/checkpoints.cpp
index 468d224..2378469 100644
--- a/sapfor/experts/Sapfor_2017/_src/Transformations/checkpoints.cpp
+++ b/sapfor/experts/Sapfor_2017/_src/Transformations/checkpoints.cpp
@@ -3,6 +3,7 @@
 #include <vector>
 #include <string>
 #include <set>
+#include <iostream>
 
 #include "../Utils/SgUtils.h"
 #include "../Utils/utils.h"