Re: Assistance: Get/Get_line

[nobody@REPLAY.COM (Anonymous)]

<355E0DE6.6867@info.polymtl.ca> <356231EB.3F2@eurocopter.de>

On Thu, 21 May 1998 12:29:24 -0400, "John J Cupak Jr, CCP"
<jcj@swl.msd.ray.com> wrote:

[about using Text_Io to input Integers (or numbers in general)]

> ...
> Alternatively, if you use Get_Line(Line, Size) to read in the
> entire line, then you can use the Integer Get from a string to
> extract just the integer part (See RM A.10.8(15-16)):
> 
>    Get_Line(Line, Size);
>    Get(From => Line(1..Size), Item => Number, Last => Last);
> ...

This (or using 'Value) is similar to the approach I recommend. I either
use a "function Get_Line return String;" or put

if Size >= Line'Last then
   Skip_Line;
end if;

after the Get_Line. Then I'm sure the entire line is gone. If there is
an error in the input, error handling is simplified if the line is gone.
Using "Get (Number);" when there is an error in the input, the required
error handling is difficult. I've seen many programs that do

output prompt

loop
   begin
      Get (Number);

      exit;
   exception
   when others =>
      output "Invalid number; re-enter"
   end;
end loop;

that work fine when the input is correct. Type an "X" for the number and
it goes into an infinite loop. Using Get_Line and really getting the
entire line eliminates this common error.

Jeff Carter  PGP:1024/440FBE21
My real e-mail address: ( carter @ innocon . com )
"Now go away or I shall taunt you a second time."
Monty Python & the Holy Grail

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