Celestin Apprentice 7/Apprentice-Release7.iso/Environments/Small Eiffel 0.4.8/lib_rand/gen_rand.e

Text File | 1997-04-13 | 1KB | 62 lines

-- Part of SmallEiffel -- Read DISCLAIMER file -- Copyright (C)
-- Dominique COLNET and Suzanne COLLIN -- [e-mail]
--
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 setting
     -- of `seed_value' (Automatic setting is done using
     -- internal address of Current for example).
      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