fc51a00.a

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-- FC51A00.A
--
--                             Grant of Unlimited Rights
--
--     Under contracts F33600-87-D-0337, F33600-84-D-0280, MDA903-79-C-0687,
--     F08630-91-C-0015, and DCA100-97-D-0025, the U.S. Government obtained 
--     unlimited rights in the software and documentation contained herein.
--     Unlimited rights are defined in DFAR 252.227-7013(a)(19).  By making 
--     this public release, the Government intends to confer upon all 
--     recipients unlimited rights  equal to those held by the Government.  
--     These rights include rights to use, duplicate, release or disclose the 
--     released technical data and computer software in whole or in part, in 
--     any manner and for any purpose whatsoever, and to have or permit others 
--     to do so.
--
--                                    DISCLAIMER
--
--     ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR
--     DISCLOSED ARE AS IS.  THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED 
--     WARRANTY AS TO ANY MATTER WHATSOEVER, INCLUDING THE CONDITIONS OF THE
--     SOFTWARE, DOCUMENTATION OR OTHER INFORMATION RELEASED, MADE AVAILABLE 
--     OR DISCLOSED, OR THE OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A
--     PARTICULAR PURPOSE OF SAID MATERIAL.
--*
--
-- FOUNDATION DESCRIPTION:
--      This foundation defines a fraction type abstraction. Fractions are
--      implemented as records with two scalar components: a numerator
--      of type integer and a denominator of type positive. Fractions are
--      created via an overloaded "/" operator.
--
-- CHANGE HISTORY:
--      06 Dec 94   SAIC    ACVC 2.0
--
--!

package FC51A00 is   -- Fraction type abstraction.

   type Fraction_Type is private;

   -- Create a fraction object by integer division.
   function "/" (Left, Right : Integer) return Fraction_Type;

   -- Change the sign of a fraction.
   function "-" (Frac : Fraction_Type) return Fraction_Type;

   -- Return value of numerator as integer.
   function Numerator (Frac : Fraction_Type) return Integer;

   -- Return value of denominator as integer.
   function Denominator (Frac : Fraction_Type) return Integer;

   -- ... Other operations on fraction types.

private

   type Fraction_Type is record
      Numerator   : Integer;
      Denominator : Positive;
   end record;

end FC51A00;


     --==================================================================--


package body FC51A00 is

   function "/" (Left, Right : Integer) return Fraction_Type is
      Result : Fraction_Type;
   begin
      Result.Numerator   := Left;
      Result.Denominator := Right;
      return Result;
   end "/";


   function "-" (Frac : Fraction_Type) return Fraction_Type is
      Result : Fraction_Type := Frac;
   begin
      Result.Numerator := -(Result.Numerator);
      return Result;
   end "-";


   function Numerator (Frac : Fraction_Type) return Integer is
   begin
      return (Frac.Numerator);
   end Numerator;


   function Denominator (Frac : Fraction_Type) return Integer is
   begin
      return (Frac.Denominator);
   end Denominator;


end FC51A00;