diff -r eff1caf6d32e -r a143f19f465b lemon/smart_graph.h
--- a/lemon/smart_graph.h	Tue Sep 29 10:39:20 2009 +0200
+++ b/lemon/smart_graph.h	Tue Sep 29 13:03:34 2009 +0200
@@ -508,7 +508,7 @@
       node._id = nodes.size() - 1;
     }
 
-    void next(Node& node) const {
+    static void next(Node& node) {
       --node._id;
     }
 
@@ -516,7 +516,7 @@
       arc._id = arcs.size() - 1;
     }
 
-    void next(Arc& arc) const {
+    static void next(Arc& arc) {
       --arc._id;
     }
 
@@ -524,7 +524,7 @@
       arc._id = arcs.size() / 2 - 1;
     }
 
-    void next(Edge& arc) const {
+    static void next(Edge& arc) {
       --arc._id;
     }