-- -- 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;