diff --git a/include/Expression.hpp b/include/Expression.hpp
index e2ecb52..00b9cc0 100644
--- a/include/Expression.hpp
+++ b/include/Expression.hpp
@@ -34,6 +34,6 @@
 
 std::optional<Operation> parseOperation(std::string& op);
 int evaluate(int a, Operation op, int b);
-int evaluate(int substitute, std::vector<std::string>::iterator& curr,
-             std::vector<std::string>::iterator&& end);
+int evaluate(int substitute, std::vector<std::string>::iterator curr,
+             std::vector<std::string>::iterator& end);
 } // namespace expression