Re: Newbie question
Date: Wed, 22 Jun 2005 16:12:41 -0700
Message-ID: <90sjb1hjq7vhcf0lgbduicit7a13v674c2_at_4ax.com>
On Thu, 23 Jun 2005 01:00:21 +0200, mAsterdam <mAsterdam_at_vrijdag.org> wrote:
[snip]
>One practical low-redundancy check is the eleven-proof
>on dutch (postbank did not join) bank-accounts, position
>from right to left:
>
> ( (sum(position * digit)) mod 11 = 0
>
>with 10 digits or less, this garantuees malformed numbers whenever:
>1 digit is mistyped
>1 digit is inserted
>2 digits changed places,
>all very common typos.
>When 2 or more digits are mistyped, there is a chance of 1/11 that the
>string is well-formed.
That is very similar to the ISBN validation. It might even be the same if the check digit is in position 1 and the value used for 10 is "X".
Sincerely,
Gene Wirchenko Received on Thu Jun 23 2005 - 01:12:41 CEST