Banking question

[Peter Klaassen - NCC vof]

see enclosed Luhn check

Peter Klaassen


From:           	"Courtney" <courtney at northshoreagency.com>
To:             	"Filepro Help List" <filepro-list at celestial.com>
Date sent:      	Mon, 29 Nov 2004 15:35:09 -0500
Copies to:      	Subject:        	Banking question

> Does anybody have a check digit routine for credit cards?  Mine does
> not seem to work for AMEX...
> 
> Courtney Karl Seith
> North Shore Agency
> 
> _______________________________________________
> Filepro-list mailing list
> Filepro-list at lists.celestial.com
> http://mailman.celestial.com/mailman/listinfo/filepro-list



-------------- next part --------------
:'Luhn Check Control for 16 digit creditcards:'Peter Klaassen - NCC - Holland - Sep.9-1999:
::declare extern creditcardnumber:
::declare global firstfifteen (15,.0):
::declare global checkdigit(1,.0):
::declare global counter(2,.0):
::declare global additionresult(3,.0):
::declare global substractionresult(3,.0):
:'fill real part of creditcardnumber:firstfifteen=mid(creditcardnumber,"1","15"):
:'fill checkdigit of creditcardnumber:checkdigit=mid(creditcardnumber,"16","1"):
::dim result (15)(1,.0):
::counter="1":
uneven:'multiply 1,3,5,7,9,11,13,15 position by 2::
:counter gt "15":counter="2";goto even:
::result(counter)=(mid(firstfifteen,counter,"1")*"2"):
:mid(firstfifteen,counter,"1") eq "5":result(counter)="1":
:mid(firstfifteen,counter,"1") eq "6":result(counter)="3":
:mid(firstfifteen,counter,"1") eq "7":result(counter)="5":
:mid(firstfifteen,counter,"1") eq "8":result(counter)="7":
:mid(firstfifteen,counter,"1") eq "9":result(counter)="9":
::counter=counter+"2";goto uneven:
even:'multiply 2,4,6,8,10,12,14 position by 1::
:counter gt "14":counter="1";goto count:
::result(counter)=mid(firstfifteen,counter,"1"):
::counter=counter+"2";goto even:
count:'add all results::
:counter gt "15":goto check:
::additionresult=additionresult+result(counter):
::counter=counter+"1";goto count:
check::'maximum of multiplying is 200:
:'deduct addition total from 200:substractionresult="200"-additionresult:
:mid(substractionresult,"3","1") eq checkdigit:end                        'check digit is ok:
:'English reply:'errorbox "Creditcardnumber is not OK":
:'Dutch reply:errorbox "Creditcardnummer is niet OK","Kies \KZ":
:'jumps back into the field:screen ,(@fd):
::end: