hungarian BBAN validation - iban

Question

can anybody tell me how to validate Hungarian BBAN account numbres ?
on the internet i have only found that it is 24 numbers length
And in format
bbbs sssk cccc cccc cccc cccx
b = National bank code
s = Branch code
c = Account number
x = National check digit
but how to calculate x = National check digit ?
I have tried to remove last char and modulo rest by 97 but it does not work
(the result is not 1 for valid account numbers)
thanks in advance for any help

Answer 1

I just finished Hungarian account validation function. This is the first version of this function but it's work well.
public string sprawdzWegierskitempAccountNumber(string _accountNumberToCheck, bool _iban) //if iban is true then function result will be always IBAN (even if _accountNumberToCheck will be BBAN)
{
string _accountNumberCorrected = _accountNumberToCheck.Replace(" ", "");
_accountNumberCorrected = _accountNumberCorrected.Replace("-", "");
_accountNumberCorrected = _accountNumberCorrected.Replace("//", "");
_accountNumberCorrected = _accountNumberCorrected.Replace("\", "");
string _accountNumberCorrectedFirst = _accountNumberCorrected;
if (_accountNumberCorrected.Length == 16 || _accountNumberCorrected.Length == 24 || _accountNumberCorrected.Length == 28)
{
if (_accountNumberCorrected.Length == 28) //IBAN Account number
{
_accountNumberCorrected = _accountNumberCorrected.Substring(4, _accountNumberCorrected.Length - 4); //we don't need first four digits (HUxx)
}
string digitToMultiply = "9731";
int checkResult = 0;
//checking first part of account number
for (int i = 0; i <= 6; i++)
{
checkResult = checkResult + int.Parse(_accountNumberCorrected.ToCharArray()[i].ToString()) * int.Parse(digitToMultiply.ToCharArray()[i % 4].ToString());
}
checkResult = checkResult % 10;
checkResult = 10 - checkResult;
if (checkResult == 10)
{
checkResult = 0;
}
if (checkResult.ToString() != _accountNumberCorrected.ToCharArray()[7].ToString())
{
throw new Exception("Wrong account number");
}
else
{
//if first part it's ok then checking second part of account number
checkResult = 0;
for (int i = 8; i <= _accountNumberCorrected.Length-2; i++)
{
checkResult = checkResult + int.Parse(_accountNumberCorrected.ToCharArray()[i].ToString()) * int.Parse(digitToMultiply.ToCharArray()[i % 4].ToString());
}
checkResult = checkResult % 10;
checkResult = 10 - checkResult;
if (checkResult == 10)
{
checkResult = 0;
}
if (checkResult.ToString() != _accountNumberCorrected.ToCharArray()[_accountNumberCorrected.Length-1].ToString())
{
throw new Exception("Wrong account number");
}
}
string tempAccountNumber = _accountNumberCorrected + "173000";
var db = 0; var iban = 0;
var maradek = 0;
string resz = "", ibanstr = "", result = "";
while (true)
{
if (db == 0)
{
resz = tempAccountNumber.Substring(0, 9);
tempAccountNumber = tempAccountNumber.Substring(9, (tempAccountNumber.Length - 9));
}
else
{
resz = maradek.ToString();
resz = resz + tempAccountNumber.Substring(0, (9 - db));
tempAccountNumber = tempAccountNumber.Substring((9 - db), (tempAccountNumber.Length - 9 + db));
}
maradek = int.Parse(resz) % 97;
if (maradek == 0)
db = 0;
else
if (maradek < 10)
db = 1;
else
db = 2;
if ((tempAccountNumber.Length + db) <= 9)
break;
}
if (maradek != 0)
{
resz = maradek.ToString();
resz = resz + tempAccountNumber;
}
else
resz = tempAccountNumber;
maradek = int.Parse(resz) % 97; ;
iban = 98 - maradek;
if (iban < 10)
ibanstr = "0" + iban.ToString();
else ibanstr = iban.ToString();
if (_accountNumberCorrected.Length == 16)
{
_accountNumberCorrected = _accountNumberCorrected + "00000000";
_accountNumberCorrectedFirst = _accountNumberCorrectedFirst + "00000000";
}
if (_iban)
{
result = "HU" + ibanstr + _accountNumberCorrected;
}
else
{
result = _accountNumberCorrectedFirst;
}
return result;
}
else
{
throw new Exception("Wrong length of account number");
}
}