Re: Leading zeros with Int_IO.Put()? Or another package?

[James Rogers <jrogers@velveeta.apdev.cs.mci.com>]

The following certainly does not qualify for the shortest solution,
but it does cover a multitude of cases.

---------------------------------------------------------------------------
-- Utility to print zero-filled strings of integer values.
---------------------------------------------------------------------------

package zero_fill is

   procedure zput (Item : in Integer; 
                   Width : in Natural := 2);

   function zput ( Item : in Integer; 
                   Width : in Natural := 2) return string;
end zero_fill;
---------------------------------------------------------------------------
-- Utility to print zero-filled strings of integer values.
---------------------------------------------------------------------------
with Ada.Text_IO;
with Ada.Numerics.Aux;

package body zero_fill is

   Package tio renames Ada.Text_IO;
   Package int_io is new tio.integer_io(integer);

   Package naux renames Ada.Numerics.Aux;

   procedure zput (Item : in Integer; 
                   Width : in Natural := 2) is
      num_digits : long_float;
      Length : Positive;
      calc_digits : Natural;
   
   begin

      num_digits := naux.log(long_float(Item)) / naux.log(10.0);
      begin
      calc_digits := natural(long_float'floor(num_digits)) + 1;
      exception
         when constraint_error =>
               tio.put_line("Conversion Error.");
               raise;
      end;
      if calc_digits  < Width then
         Length := Natural(Num_Digits) + 1;
      else
         Length := Width;
      end if;

      declare
         out_string : string(1..Length);
      begin
         int_io.put(out_string, Item);
         for Index in reverse out_string'Range loop
            if out_string(Index) not in '0'..'9' then
               out_string(Index) := '0';
            end if;
         end loop;
         tio.put(out_string);
      end;
   end zput;

   function zput ( Item : in Integer; 
                   Width : in Natural := 2) return string is
      num_digits : long_float;
      Length : Positive;
      
   begin

      num_digits := naux.log(long_float(Item)) / naux.log(10.0);
      if Natural(num_digits) + 1  < Width then
         Length := Natural(Num_Digits) + 1;
      else
         Length := Width;
      end if;

      declare
         out_string : string(1..Length);
      begin
         int_io.put(out_string, Item);
         for Index in reverse out_string'Range loop
            if out_string(Index) not in '0'..'9' then
               out_string(Index) := '0';
            end if;
         end loop;
         return out_string;
      end;
   end zput;
end zero_fill;

-- 
Jim Rogers
*************************************************************
Team Ada