--          This file is part of SmallEiffel The GNU Eiffel Compiler.
--          Copyright (C) 1994-98 LORIA - UHP - CRIN - INRIA - FRANCE
--            Dominique COLNET and Suzanne COLLIN - colnet@loria.fr
--                       http://www.loria.fr/SmallEiffel
-- SmallEiffel is  free  software;  you can  redistribute it and/or modify it
-- under the terms of the GNU General Public License as published by the Free
-- Software  Foundation;  either  version  2, or (at your option)  any  later
-- version. SmallEiffel is distributed in the hope that it will be useful,but
-- WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
-- or  FITNESS FOR A PARTICULAR PURPOSE.   See the GNU General Public License
-- for  more  details.  You  should  have  received a copy of the GNU General
-- Public  License  along  with  SmallEiffel;  see the file COPYING.  If not,
-- write to the  Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-- Boston, MA 02111-1307, USA.
--
class HANOI
   --
   -- The classic Tower of Hanoi game.
   --
   -- Compile with :
   --    compile -o hanoi hanoi -boost
   -- Run with :
   --    hanoi
   --

inherit
   ANY redefine out_in_tagged_out_memory
      end;

creation make

feature {NONE}

   nb: INTEGER;

   t1, t2, t3 : TOWER;

feature

   make is
      do
         io.put_string("Type the number of discus, please : ");
         io.flush;
         io.read_integer;
         nb := io.last_integer;
         !!t1.full(nb);
         !!t2.empty(nb);
         !!t3.empty(nb);
         io.put_string("Situation at the beginning : %N");
         move(nb,t1,t2,t3);
         io.put_string("Situation at the end : %N");
         print_on(io);
      end;

   move(how_many: INTEGER; source, intermediate, destination: TOWER) is
      local
         discus: INTEGER;
      do
         if (how_many > 0) then
            move(how_many-1,source,destination,intermediate);
            print_on(io);
            discus := source.remove_discus;
            destination.add_discus(discus);
            move(how_many-1,intermediate,source,destination);
         end;
      end;

   out_in_tagged_out_memory is
      local
         i: INTEGER;
      do
         tagged_out_memory.extend('%N');
         from
            i := nb;
         until
            i = 0
         loop
            tagged_out_memory.extend(' ');
            t1.show_a_discus(i,tagged_out_memory);
            tagged_out_memory.extend(' ');
            t2.show_a_discus(i,tagged_out_memory);
            tagged_out_memory.extend(' ');
            t3.show_a_discus(i,tagged_out_memory);
            tagged_out_memory.extend('%N');
            i := i - 1;
         end;
         from
            i := (((2 * (nb + 1)) + 1) * 3) - 2;
         until
            i = 0
         loop
            tagged_out_memory.extend('-');
            i := i - 1;
         end;
         tagged_out_memory.extend('%N');
      end;
end -- HANOI