Luhn Check: Is the credit card number you are a - Visual Basic , VB.NET

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Luhn Check: Is the credit card number you are a...
Author: Gabe Harris
E-mail: Click to e-mail author
Submitted: 8/2/2000
Version: VB6
Compatibility: VB6
Category:
Views: 11758
Luhn Check: Is the credit card number you are accpeting a Valid #? if the function returns a 1 then the # is Luhn 10 valid...if it returns a 0 then the CC# is not valid.
Declarations:
'none
Code:
' the Luhn function need isodd() and ismodten() in 'order to work Function IsOdd(x) If Right(x, 1) = 1 Or Right(x, 1) = 3 Or Right(x, 1) = 5 Or Right(x, 1) = 7 Or Right(x, 1) = 9 Then IsOdd = 1 Else IsOdd = 0 End If End Function 'Line9 Function IsModTen(x) If Right(Trim(x), 1) = 0 Then IsModTen = 1 Else IsModTen = 0 End If End Function 'Line18 'this is Function LUHN(x) temp = 0 a = 0 i = 0 l = Len(x) For i = 1 To l a = Mid(x, l + 1 - i, 1) If IsOdd(i) = 1 Then temp = temp + a Else a = 2 * a If a > 9 Then a = Left(a, 1) + Right(a, 1) End If temp = temp + a End If Next i If IsModTen(temp) = 1 Then LUHN = 1 Else LUHN = 0 End If End Function