Re: Newbie question on Ada TExt_IO

["David C. Hoos" <david.c.hoos.sr@ada95.com>]

----- Original Message -----
From: "Justin" <jbirtwell@yahoo.com>
Newsgroups: comp.lang.ada
To: <comp.lang.ada@ada.eu.org>
Sent: Thursday, October 03, 2002 1:20 PM
Subject: Newbie question on Ada TExt_IO


> Hi,
>
> I'm relatively new to Ada.  I've read 1/2 of Programming in Ada95 by
> Barnes, done half of Lovelace and read as much as I can stomach of the
> Ada RM. Forgive me if this question is too basic, but I've been unable
> to see any reference to it in the previous documentation.
>
> I'm doing TextIO from the command prompt.  But I'm having difficulty
> validating the input.  For example I'm asking the user to enter a
> number, let's say I'm expecting an integer between 1 and 6
>
> X:Integer;
> ...
> Put("Please enter a number between 1 and 6);
> Get(x);
>
> But what if they give me 'abc' or 4.44 or simply
> 1230000000000000000000000000000000000000000000000000000000000000000000000
>
First, I would be sure that the user prompt is precise in defining the
desired input.  4.44 _is_ "number between 1 and 6". If what you meant
is "Please enter an integer from 1 to 6 inclusive", I would say just that.

> How can I handle this?  From my take on what I've read I should avoid
> exception handling for things I'm not expecting, so I've ruled out
> exceptions, that leaves me with obtaining a value of generic type and
> evalutating the type at run-time...how can I do this?  Is this the
> right strategy?
I have seen some discussion deprecating the use of exception handlers for
validating user input, but frankly, I've never been convinced, and I use
them.

>
> Thanks for they help,
> Justin
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