IBANChecker.xlsm

Function my_convert(ch As String) As String

    Dim dict As New Scripting.Dictionary 'Nécessite d'importer Microsoft Scripting Runtime

    dict.Add Key:="A", Item:=10
    dict.Add Key:="B", Item:=11
    dict.Add Key:="C", Item:=12
    dict.Add Key:="D", Item:=13
    dict.Add Key:="E", Item:=14
    dict.Add Key:="F", Item:=15
    dict.Add Key:="G", Item:=16
    dict.Add Key:="H", Item:=17
    dict.Add Key:="I", Item:=18
    dict.Add Key:="J", Item:=19
    dict.Add Key:="K", Item:=20
    dict.Add Key:="L", Item:=21
    dict.Add Key:="M", Item:=22
    dict.Add Key:="N", Item:=23
    dict.Add Key:="O", Item:=24
    dict.Add Key:="P", Item:=25
    dict.Add Key:="Q", Item:=26
    dict.Add Key:="R", Item:=27
    dict.Add Key:="S", Item:=28
    dict.Add Key:="T", Item:=29
    dict.Add Key:="U", Item:=30
    dict.Add Key:="V", Item:=31
    dict.Add Key:="W", Item:=32
    dict.Add Key:="X", Item:=33
    dict.Add Key:="Y", Item:=34
    dict.Add Key:="Z", Item:=35


    If dict.Exists(ch) Then
        my_convert = dict(ch)
    Else
        my_convert = ch
    End If
End Function

Sub IBANChecker():

    Dim rib As String

    rib = Replace(Replace(ActiveCell.Value, " ", ""), "-", "") 'Supprimer les caratères indésirables
    rib2 = Right(rib, Len(rib) - 4) & Left(rib, 4) 'Placer les 4 premiers caractères à la fin

    resultat = 0
    Dim ch As String

    For n = 1 To Len(rib2)

        ch = Mid(rib2, n, 1)

        If IsNumeric(ch) Then 'Tour de magie mathématique pour optimiser les calculs..
            resultat = (10 * resultat + ch) Mod 97
        Else
            resultat = (100 * resultat + my_convert(ch)) Mod 97
        End If

    Next n

    If (resultat = 1) Then
        MsgBox ("L'IBAN est correct")
    Else
        MsgBox ("L'IBAN est incorrect :'( ")
    End If
End Sub