Re: Newbie Question: Integer_IO an Data_error

[Jean-Pierre Rosen <rosen@adalog.fr>]

Tim Rowe a �crit :
> Zachary Kline wrote:
>> The problem comes with Data_errors: if I try to
>> handle that case the same way, we get a seemingly infinite loop.
> 
> 
> I'm an Ada newbie too, but the first thing I wonder is what Get does
> with the input characters if they don't match the expected type. I
> wonder whether it leaves them on the input stream -- in which case
> subsequent attempts to read the input will try to read the same
> characters each time. Until somebody who knows what they're talking
> about comes along (won't be long) I'd try doing a string Get after a
> failed numeric get, to see what's still in the input stream.

When a character is incorrect, the current position stays on it, to
allow you to do a Get(Char) and see what happened. OTOH, it means that
you must do a skip_line to get rid of the remaining of the line, and get
a fresh one. A typical reading loop is:

loop
   begin
      Get (N);
      exit;    -- OK, no exception
   exception
      when Data_Error =>
         Skip_Line;
         Put_Line ("Error, try again");
   end;
end loop;

-- 
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           J-P. Rosen (rosen@adalog.fr)
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