--- a/src/utils.hpp
+++ b/src/utils.hpp
@@ -2,6 +2,9 @@
 #define _UTILS_HPP_
 
 #include <string>
+#include <stdio.h>
+#include <cstdlib>
+
 using std::string;
 
 extern bool stdio_getline(FILE *in, string &str);