1.1 --- a/lemon/elevator.h	Mon Feb 19 19:55:13 2007 +0000
     1.2 +++ b/lemon/elevator.h	Tue Feb 20 12:55:37 2007 +0000
     1.3 @@ -146,6 +146,9 @@
     1.4      }
     1.5    
     1.6      ///Activate item \c i.
     1.7 +
     1.8 +    ///Activate item \c i.
     1.9 +    ///\pre Item \c i shouldn't be active before.
    1.10      void activate(Item i)
    1.11      {
    1.12        const int l=_level[i];
    1.13 @@ -154,6 +157,9 @@
    1.14      }
    1.15    
    1.16      ///Deactivate item \c i.
    1.17 +
    1.18 +    ///Deactivate item \c i.
    1.19 +    ///\pre Item \c i must be active before.
    1.20      void deactivate(Item i)  
    1.21      {
    1.22        swap(_where[i],_last_active[_level[i]]--);