class WALL

      -- A wall for the bottles

creation

   make

feature

   make (init_bottles: INTEGER) is
      require
         positive_bottles: init_bottles >= 0
      do
         bottles := init_bottles
      end

   remove is
      require
         bottles_exist: bottles > 0
      do
         bottles := bottles - 1
      end

   bottles: INTEGER

   description: STRING is
      do
         if bottles = 0 then
            Result := "No"
         else
            Result := bottles.out
         end
         Result.append (" bottle")
         if bottles /= 1 then
            Result.append ("s")
         end
         Result.append (" of beer")
      end

   empty: BOOLEAN is
      do
         Result := bottles = 0
      end


end -- class WALL