-- -*-ada-*-
-- =====================================================================
-- Print ascending members of the Fibonacci sequence that are
-- representable as 64-bit signed integers, prefixed by their term
-- numbers, and followed by the ratio of successive terms, to
-- demonstrate the 1.618...^n growth (the ratio approaches the golden
-- ratio, (1 + sqrt(5))/2 = 1.6180339887498949, and reaches it (to
-- machine precision) at 41 terms: the fourth item on each line is
-- the difference from the golden ratio).
-- =====================================================================

with Ada.Text_IO;
use  Ada.Text_IO;

with Ada.Long_Long_Integer_Text_IO;
use  Ada.Long_Long_Integer_Text_IO;

with Ada.Long_Long_Float_Text_IO;
use  Ada.Long_Long_Float_Text_IO;

with Ada.Numerics.Long_Long_Elementary_Functions;
use  Ada.Numerics.Long_Long_Elementary_Functions;

procedure Fibonacci3 is
  Golden_Ratio : Long_Long_Float := (1.0 + Sqrt(5.0))/2.0;
  Lo : Long_Long_Integer := 1;
  Hi : Long_Long_Integer := 1;
  N : Long_Long_Integer := 1;
  Ratio : Long_Long_Float;
begin
    Put(N, Width => 2);
    Put(Lo);
    New_Line;
    while Hi > 0 loop
        N := N + 1;
        Ratio := Long_Long_Float(Hi)/Long_Long_Float(Lo);
        Put(N, Width => 2);
        Put(ASCII.HT);
        Put(Hi, Width => 19);
        Put(ASCII.HT);
        Put(Ratio, Fore => 2, Aft => 15, Exp => 0);
        Put(ASCII.HT);
        Put(Ratio - Golden_Ratio, Fore => 2, Aft => 15, Exp => 0);
        New_Line;
        Hi := Lo + Hi;
        Lo := Hi - Lo;
    end loop;
end Fibonacci3;