Re: AVR Usart send number string with no 'Image

[Simon Wright <simon@pushface.org>]

"Rego, P." <pvrego@gmail.com> writes:

> I tried this, but the compiler pointed that I could not use the second
> stack, so this recursion is not allowed.

Iteration is your friend.

I thought I might find an answer via google, SO or Rosetta Code, but
no. So try this:

with Ada.Text_IO; use Ada.Text_IO;
with Interfaces;
procedure U8_To_String is

   --  If we can't use the secondary stack, we can't write functions
   --  that return unconstrained arrays. We know there can never be
   --  more than 3 decimal digits in the output.
   subtype Output_String is String (1 .. 3);

   function To_String (U : Interfaces.Unsigned_8) return Output_String is
      Result : Output_String := (others => ' ');
      use type Interfaces.Unsigned_8;
      Digit : Interfaces.Unsigned_8 := U mod 10;
      Rest_Of_Number : Interfaces.Unsigned_8 := U / 10;
   begin
      for J in reverse Result'Range loop
         if Digit /= 0
           or else Rest_Of_Number /= 0
           or else J = Result'Last then
            Result (J)
              := Character'Val (Character'Pos ('0') + Integer (Digit));
         end if;
         Digit := Rest_Of_Number mod 10;
         Rest_Of_Number := Rest_Of_Number / 10;
         -- could exit when Rest_Of_Number = 0
      end loop;
      return Result;
   end To_String;

begin
   Put_Line (To_String (0));
   Put_Line (To_String (90));
   Put_Line (To_String (99));
   Put_Line (To_String (100));
   Put_Line (To_String (101));
   Put_Line (To_String (142));
   Put_Line (To_String (200));
   Put_Line (To_String (201));
   Put_Line (To_String (242));
   Put_Line (To_String (255));
end U8_To_String;