-- This file is  free  software, which  comes  along  with  SmallEiffel. This
-- software  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. You can modify it as you want, provided
-- this header is kept unaltered, and a notification of the changes is added.
-- You  are  allowed  to  redistribute  it and sell it, alone or as a part of 
-- another product.
--          Copyright (C) 1994-98 LORIA - UHP - CRIN - INRIA - FRANCE
--            Dominique COLNET and Suzanne COLLIN - colnet@loria.fr 
--                       http://www.loria.fr/SmallEiffel
--
deferred class GEN_RAND
   -- 
   -- Here is the common way to use a random number generator.
   -- Current implementations are MIN_STAND, STD_RAND.
   --

feature {NONE} -- Creation procedures:

   make is
	 -- Create the generator with an automatic hazardous setting of
	 -- the `seed_value'.
	 -- Because automatic setting may be done using internal address
	 -- of Current for example, it may produces platform dependent 
	 -- behavior or compilation-mode dependant behavior.
	 -- Also consider `with_seed' to chose the most appropriate.
      deferred
      end;

   with_seed(seed_value: INTEGER) is
	 -- Create the generator with an explicit `seed_value'.
      deferred
      end;

feature
   
   next is
	 -- Compute next random number in sequence.
      deferred
      end;

feature -- No modifications :
   
   last_double: DOUBLE is
	 -- Look at the last computed number.
	 -- Range 0 to 1;
      do
	 Result := last_real.to_double;
      ensure
	 Result > 0 and Result < 1
      end;
   
   last_real: REAL is
	 -- Look at the last computed number.
	 -- Range 0 to 1;
      deferred
      ensure
	 Result > 0 and Result < 1
      end;
   
   last_integer(n:INTEGER):INTEGER is
	 -- Look the last computed number.
	 -- Range 1 to `n'.
      require 
	 n >= 1
      deferred
      ensure
	 1 <= Result and Result <= n
      end;

end -- GEN_RAND