diff --git a/src/SimpleRandomizer.cc b/src/SimpleRandomizer.cc
index ed27d586..72ead48b 100644
--- a/src/SimpleRandomizer.cc
+++ b/src/SimpleRandomizer.cc
@@ -34,9 +34,10 @@
 /* copyright --> */
 #include "SimpleRandomizer.h"
 
-#include <cstdlib>
 #include <sys/types.h>
 #include <unistd.h>
+#include <cstdlib>
+#include <cassert>
 
 #include "a2time.h"