diff --git a/u01/node.cpp b/u01/node.cpp
index b1ff337..0d3ce9c 100644
--- a/u01/node.cpp
+++ b/u01/node.cpp
@@ -29,7 +29,7 @@ node::~node() {
 
 std::string node::get_name() const { return name; }
 
-void node::set_name(const std::string new_name) { this->name = new_name; }
+void node::set_name(const std::string& new_name) { this->name = new_name; }
 
 std::size_t node::get_nr_children() const { return children.size(); }
 
diff --git a/u01/node.h b/u01/node.h
index def10b3..763081f 100644
--- a/u01/node.h
+++ b/u01/node.h
@@ -11,7 +11,7 @@ public:
   node(const std::string &name = "");
   virtual ~node();
   std::string get_name() const;
-  void set_name(const std::string new_name);
+  void set_name(const std::string &new_name);
   std::size_t get_nr_children() const;
   node *get_child(std::size_t i) const;
   void add_child(node *child);