diff --git a/cpp/exports.hpp b/cpp/exports.hpp
index 8be142765b6e1d9e4d7aafa700f6d8b67d67655a..c6128061badfc045b382378814af6b0c2921cf88 100644
--- a/cpp/exports.hpp
+++ b/cpp/exports.hpp
@@ -1,4 +1,5 @@
 #pragma once
+#include <iostream>
 #include "graph.hpp"
 
 std::ostream &operator<<(std::ostream &s, const Edge &e) {