diff --git a/lib/util.C b/lib/util.C
index 2c6758e9dc..65d1fe920f 100755
--- a/lib/util.C
+++ b/lib/util.C
@@ -29,6 +29,7 @@
 #include <cstdio>
 #include <cmath>
 #include <algorithm>
+#include <iterator>
 #include <fstream>
 #include <ctype.h>
 #include <sys/types.h>