diff --git a/src/memory.cpp b/src/memory.cpp
index 072e2c5..f33e383 100644
--- a/src/memory.cpp
+++ b/src/memory.cpp
@@ -21,6 +21,7 @@
 #include <algorithm>
 #include <istream>
 #include <cstdlib>
+#include <cstddef>
 #include "raminitializer.h"