MODULE Fibonacci3o;

(***********************************************************************
Print ascending members of the Fibonacci sequence that are representable
as 32-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).
***********************************************************************)

IMPORT	Ascii,
	LRealMath,
	StdChannels,
        TextRider;

VAR
   lo		: LONGINT;
   hi		: LONGINT;
   n		: LONGINT;

   diff		: LONGREAL;
   golden_ratio	: LONGREAL;
   ratio	: LONGREAL;

   writer       : TextRider.Writer;

BEGIN
   writer := TextRider.ConnectWriter(StdChannels.stdout);
   golden_ratio := (1.0D0 + LRealMath.sqrt(5.0D0))/2.0D0;
   lo := 1;
   hi := 1;
   n := 1;
   writer.WriteLInt(n, 2);
   writer.WriteChar (Ascii.ht);
   writer.WriteLInt(lo, 12);
   writer.WriteLn;
   WHILE (hi > 0) DO
      n := n + 1;
      ratio := hi;
      ratio := ratio / lo;
      writer.WriteLInt(n, 2);
      writer.WriteChar (Ascii.ht);
      writer.WriteLInt(hi, 12);
      writer.WriteChar (Ascii.ht);
      writer.WriteLRealFix(ratio, 25, 15);
      writer.WriteChar (Ascii.ht);
      diff := ratio - golden_ratio;
      writer.WriteLRealFix(diff, 25, 15);
      writer.WriteLn;
      hi := lo + hi;
      lo := hi - lo
   END
END Fibonacci3o.