Function IBANCheck

PARAMETERS pIban2Check
** 1st move first 4 digits to the end
cAcntnmbr2Chck = ALLTRIM(SUBSTR(pIban2Check,5,50))+LEFT(pIban2Check,4)
cAcntInNmbrs = ''
** change all letters into numbers
FOR x = 1 TO LEN(ALLTRIM(cAcntnmbr2Chck))
cAcntInNmbrs = cAcntInNmbrs+TRANSF(IIF(ISALPHA((SUBSTR(cAcntnmbr2Chck,x,1))),;
(ASC(LOWER((SUBSTR(cAcntnmbr2Chck,x,1))))-87),(SUBSTR(cAcntnmbr2Chck,x,1))))
ENDFOR
** Ibannumbers can be > 32 digits FoxPro can't handle these numbers
** so chop into acceptable portions
cMod = TRANSFORM(MOD(VAL(SUBSTR(cAcntInNmbrs,1,9)),97))
FOR T = 10 TO 24 STEP 7
cMod = TRANSFORM(MOD(VAL(cMod+SUBSTR(cAcntInNmbrs,T,7)),97))
ENDFOR
nResult = VAL(cMod)
* nResult = 1 = passed Iban test

Take care, I have given you the code to valid-check if a given bankaccount number is a valid IBAN number. I have not given you the code to construct an IBAN. This could be done easy enough as well but is also highly UNrecommended. It could lead to wrong solutions. Customers should never construct themselves an IBAN number, this should always be collected from their bank.
In case you publish an 'IBAN-maker' you are facing troubles with the European Banking Athority.

Regards,
Koen