From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.5-pre1 (2020-06-20) on
	ip-172-31-74-118.ec2.internal
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=3.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.5-pre1
Path: eternal-september.org!reader02.eternal-september.org!aioe.org!5WHqCw2XxjHb2npjM9GYbw.user.gioia.aioe.org.POSTED!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: From_string(Arg : String) return Big_Integer
Date: Sun, 10 Jan 2021 17:02:59 +0100
Organization: Aioe.org NNTP Server
Message-ID: <rtf8fh$1mmv$1@gioia.aioe.org>
References: <c4cce4e8-8b69-4a0a-b628-921c1b845dcfn@googlegroups.com>
 <fc7db0da-59f3-4b50-be41-98b8f3eb8ca5n@googlegroups.com>
 <5126648c-215e-4d9e-bdd9-82fa5b510896n@googlegroups.com>
 <5ffa2a7b$0$19459$426a74cc@news.free.fr> <rteidn$1to4$1@gioia.aioe.org>
 <5ffb21c8$0$21590$426a74cc@news.free.fr>
NNTP-Posting-Host: 5WHqCw2XxjHb2npjM9GYbw.user.gioia.aioe.org
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
X-Complaints-To: abuse@aioe.org
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101
 Thunderbird/78.6.0
X-Notice: Filtered by postfilter v. 0.9.2
Content-Language: en-US
Xref: reader02.eternal-september.org comp.lang.ada:61089
List-Id: <comp.lang.ada>

On 2021-01-10 16:48, DrPi wrote:

> So either :
> 
>        for C of Str loop
>           Num := (Num * 10) + Character'Pos (C) - Character'Pos ('0');
>        end loop;
> 
> or :
> 
>        for Idx in Str'Range loop
>           Num := (Num * 10) + Character'Pos (Str(Idx)) - Character'Pos 
> ('0');
>        end loop;

Just for fun:

    subtype Digit is Character range '0'..'9';
    Encode : constant array (Digit) of Integer := (0,1,2,3,4,5,6,7,8,9);

    for ... loop
       Num := Num * 10 + Encode (C);

>> - It does not handle overflow;
> It handles overflow.

Only if Constraint_Error must be the result.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de