Check Digit formula

[Abdul]

Dear all,

I have the following serial numbers:

41078928128
41078928136
41078928144
41078928151
41078928169
41078928177
41078928185
41078928193
41078928201

The last digit is a check digit. How can I get the formula /algorithm
to get the check digit? So that if I have the serial numbers I can add
the check digit with it?

Thanks

 

[Gary''s Student]

see:

http://groups.google.com/group/micr...a384?lnk=gst&q="check+digit"#b0d7fd6324bfa384

 

[FSt1]

hi
assuming all of your serial numbers are the same length and start in A1,
this formula will get your check digit
=right(A1,1)
but i don't understand the rest of your question.


Regards
FSt1

 

[Joel]

There are lots of different check bit algorithms. It look like you values
meet the Luhn algorithm. I did not check the code below that I got from
en.wikipedia.org. You can get more info from Wikpedia.

Public Function ValidateCardNumber(strCardNumber) As Boolean ' MOD 10 check
digit. "Luhn algorithm"
On Error GoTo Err

Dim intLoop As Integer, intSum As Integer
Dim bIsAlternate As Boolean, intProduct As Integer

For intLoop = Len(strCardNumber) To 1 Step -1

If bIsAlternate = False Then
intSum = intSum + CInt(Mid(strCardNumber, intLoop, 1))
bIsAlternate = True
Else

intProduct = CInt(Mid(strCardNumber, intLoop, 1)) * 2

If Len(CStr(intProduct)) = 2 Then
intSum = intSum + CInt(Mid(intProduct, 1, 1)) +
CInt(Mid(intProduct, 2, 1))
Else
intSum = intSum + CInt(intProduct)
End If

bIsAlternate = False

End If

Next intLoop

If intSum Mod 10 = 0 Then
ValidateCardNumber = True
Else
ValidateCardNumber = False
End If

Exit Function

Err:
MsgBox "Error in ValidateCardNumber()" & vbCrLf & Err.Number &
Err.Description
End Function

 

[Gary''s Student]

I think he wants to know how to calculate the 11th digit starting with 10
digit data.

 

[Abdul]

Thanks Mike and all other posters.

Great.
The initial testing shows i have got what I am looking for.

Thanks again

 

[Rick Rothstein \(MVP - VB\)]

However, for Excel:

=MOD(789-1,9)+1
=6

I believe, for Excel's MOD function, you need to use the following instead
of the above?

=MOD(MOD(B1-1,9)+1,9)

Without the second MOD function, numbers like 0, 891, 333, etc. (that is,
numbers whose digits total 9) will return 9 instead of what I think should
be 0. If you do this in VBA, then the second MOD function call should not be
necessary.

Rick

 

[Dana DeLouis]

If we wish to get rid of the IF statement, one idea...

Function GenerateCheckDigit(n) As Long
Dim Fg As Boolean 'flag
Dim P As Long
Dim T As Long

'// Odd positions values are doubled
Fg = Len(n) Mod 2 = 1 'Odd?
For P = 1 To Len(n)
T = T + (((1 - Fg) * (Mid(n, P, 1)) - 1) Mod 9) + 1
Fg = Not Fg
Next P
GenerateCheckDigit = (10 - (T Mod 10)) Mod 10
End Function

--
Dana DeLouis