Utilisable en VBA (excel, word…)

Public Function Gencod(codeGen) As Boolean
'Cette fonction renvoie true si le GENCOD n'est pas valide

Dim wcod As String
Dim x As Integer
Dim totPair, totImpair, totGen As Long
Dim cle, w10 As Integer
Gencod = False
wcod = Len(Trim(codeGen))
If wcod <> 13 Or IsNumeric(Trim(codeGen)) = False Then
Gencod = True
Exit Function
End If
For x = 1 To 12
If x Mod 2 = 0 Then
'pair
totPair = totPair + CInt(Mid(Trim(codeGen), x, 1))
Else
'impair
totImpair = totImpair + CInt(Mid(Trim(codeGen), x, 1))
End If
Next x
totGen = (totPair * 3) + totImpair
w10 = Fix(totGen / 10) + 1
cle = (w10 * 10) - totGen
if cle >= 10 then cle = 0
If cle <> CInt(Mid(codeGen, 13, 1)) Then
Gencod = True
Exit Function
End If
End Function