[RESOLVED] working with very long numbers !!!

[dilettante]

Condensing down that truly awful code offered by the Central Bank of Malta...

... there isn't much to it.

No long numbers at all, you just have to look up the algorithm and go, or as in this case find some working but nasty code and clean it up.

Function Validate_IBAN(ByVal Account As String) As Boolean
    Dim intChar As Integer
    Dim strChar As String
    
    Account = UCase$(Account)
    If Len(Account) > 4 Then Account = Mid$(Account, 5) & Left$(Account, 4)
    intChar = Len(Account)
    Do While intChar > 0
        strChar = Mid$(Account, intChar, 1)
        If strChar Like "[A-Z]" Then
            '55 = Asc("A") - 10
            Account = Left$(Account, intChar - 1) _
                   & CStr(Asc(strChar) - 55) _
                   & Mid$(Account, intChar + 1)
        End If
        intChar = intChar - 1
    Loop
    Do While Len(Account) > 5
        Account = CStr(CLng(Left$(Account, 5)) Mod 97) & Mid$(Account, 6)
    Loop
    Validate_IBAN = (CLng(Account) Mod 97) = 1
End Function

Seems to work against the handful of examples I found (included in the program in a dropdown ComboBox).