Integer Stack Demonstration Client

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Rational Number Package Body

--
-- An ADT to represent positive rational numbers.
--
package Rational_Number is
   -- The type of the objects.
   type Rational is private;

   -- Get there from an integer or pair of integers.
   function To_Rational(Num: Integer; Den: Integer := 1) return Rational;

   -- Output a rational.
   procedure Put(R: Rational);

   -- Four functions.
   function "+" (A, B: Rational) return Rational;
   function "-" (A, B: Rational) return Rational;
   function "*" (A, B: Rational) return Rational;
   function "/" (A, B: Rational) return Rational;

   -- We need to take over the equality function, otherwise 6/8 /= 3/4.
   function "=" (A, B: Rational) return Boolean;

   private
      -- Just remember numerator and denominator.
      subtype Unsigned is Integer range 0..16#7fffffff#;
      type Rational is record
         Num, Denom: Unsigned;
      end record;
end Rational_Number;

Integer Stack Demonstration Client

Rational Number Package Body