diff --git a/src/graph_manager.cpp b/src/graph_manager.cpp
index af79551..710597e 100644
--- a/src/graph_manager.cpp
+++ b/src/graph_manager.cpp
@@ -1,5 +1,6 @@
 #include "graph_manager.h"
 
+#include <fstream>
 #include <iostream>
 #include <algorithm>
 #include <cstdlib>