ValidCard ( pNumber ; pShow )

ValidCard checks the plausibility of a given cardnumber and gives back the check digit or if you want the name of the card.

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Klaus-Dieter Bruegmann - Show more from this author
kade project
http://www.kade-project.de

Sample input:

complete card number ; ""

complete card number ; "Card"

Sample output:

check digit

card name

(or "input error")

Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

/**************************************

Author: kade, Klaus-Dieter Brügmann
www.kade-project.de
Input the complete cardnumber!
**************************************/

Let (
[
Error = Case ( Length ( pNumber ) <> Length ( Filter ( pNumber ; "0123456789" ) )
or Length ( pNumber ) < 13 or Length ( pNumber ) > 16 ; "input error" ; "" ) ;

TheNumber = Right ( "0000" & Filter ( pNumber ; "0123456789" ) ; 16 ) ;

CN = Right ( 10 -
Mod (
Middle ( TheNumber ; 14 ; 1 ) +
Middle ( TheNumber ; 12 ; 1 ) +
Middle ( TheNumber ; 10 ; 1 ) +
Middle ( TheNumber ; 8 ; 1 ) +
Middle ( TheNumber ; 6 ; 1 ) +
Middle ( TheNumber ; 4 ; 1 ) +
Middle ( TheNumber ; 2 ; 1 ) +

Middle ( TheNumber ; 15 ; 1 ) * 2 - Case ( Middle ( TheNumber ; 15 ; 1 ) * 2 > 9 ; 9 ; 0) +
Middle ( TheNumber ; 13 ; 1 ) * 2 - Case ( Middle ( TheNumber ; 13 ; 1 ) * 2 > 9 ; 9 ; 0) +
Middle ( TheNumber ; 11 ; 1 ) * 2 - Case ( Middle ( TheNumber ; 11 ; 1 ) * 2 > 9 ; 9 ; 0) +
Middle ( TheNumber ; 9 ; 1 ) * 2 - Case ( Middle ( TheNumber ; 9 ; 1 ) * 2 > 9 ; 9 ; 0 ) +
Middle ( TheNumber ; 7 ; 1 ) * 2 - Case ( Middle ( TheNumber ; 7 ; 1 ) * 2 > 9 ; 9 ; 0 ) +
Middle ( TheNumber ; 5 ; 1 ) * 2 - Case ( Middle ( TheNumber ; 5 ; 1 ) * 2 > 9 ; 9 ; 0 ) +
Middle ( TheNumber ; 3 ; 1 ) * 2 - Case ( Middle ( TheNumber ; 3 ; 1 ) * 2 > 9 ; 9 ; 0 ) +
Middle ( TheNumber ; 1 ; 1 ) * 2 - Case ( Middle ( TheNumber ; 1 ; 1 ) * 2 > 9 ; 9 ; 0 ) ;
10 ) ; 1 ) ;
TheCard =
Case ( CN = Right ( pNumber ; 1 ) ;
Case ( Left ( pNumber ; 1 ) = 4 ; "Visa" ;
Length ( pNumber ) = 16 ;
Case ( Left ( pNumber ; 4 ) = 6011 ; "Discover" ;
Left ( pNumber ; 2 ) >= 51 and Left ( pNumber ; 2 ) <= 55 ; "Mastercard (Eurocard, Credicard)" ;
Left ( pNumber ; 2 ) >= 70 ; "Bahncard"; "Unknown") ;
Length ( pNumber ) = 15 ;
Case ( Left ( pNumber ; 2 ) = 34 or Left ( pNumber ; 2 ) = 37; "American Express" ;
Left ( pNumber ; 4 ) = 2014 or Left ( pNumber ; 4 ) = 2149; "En Route";
Left ( pNumber ; 4 ) = 2131 or Left ( pNumber ; 4 ) = 1800; "JCB";
Left ( pNumber ; 2 ) = 99 or Left ( pNumber ; 2 ) = 22; "Miles&More" ; "Unknown" ) ;
Length ( pNumber ) = 14 ;
Case ( Left ( pNumber ; 2 ) = 36 or Left ( pNumber ; 2 ) = 38
or ( Left ( pNumber ; 4 ) >= 300 and Left ( pNumber ; 4 ) <= 305) ; "Diner's Club" ; "Unknown") ;
"Unknown")
; Error)
];

If ( not IsEmpty ( pNumber ) ;
Case ( not IsEmpty ( Error) ; Error ;
IsEmpty ( pShow ) or pShow = "Check digit" ; CN ;
pShow = "Card" ; TheCard ; "Input error" )
; "")
)

ValidCard checks the plausibility of a given cardnumber and gives back the check digit or if you want the name of the card. You can check various types of cards: American Express, Diner's Club, Visa, Mastercard, Discover, JCB, En Route and also the german "Bahncard" and the "Miles&More" card of the german airline "Lufthansa".

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Note: these functions are not guaranteed or supported by BrianDunning.com. Please contact the individual developer with any questions or problems.

ValidCard ( pNumber ; pShow )

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