Rechercher le lundi de la semaine N°

Sub Bouton1_Cliquer()
    Dim DDate As Date
    
    With Worksheets("feuil1")
        'ici annee en cours
        DDate = "03/01/" & Year(Date)
        NDay = Weekday(DDate, vbMonday)     'Numero jour semaine de la date (Lundi: premier jour de la semaine)
        Num_sem = .Range("A1")                        'numero de semaine
        'calcul date lundi de la semaine
        lundi = DDate - NDay - 5 + (7 * Num_sem) - 1
        'affichage
        .Range("B1") = lundi
        .Range("C1") = lundi + 6
        
    End With
End Sub

    Public Function Lundi(Num_Semaine As Integer, Annee As Integer) As Date
    Dim Jour As Integer, Debut_Annee As Date
    
        Jour = (DateSerial(Annee, 1, 1) - 2) Mod 7
        If Jour < 4 Then
            Debut_Annee = DateSerial(Annee, 1, 1) - Jour
        Else
            Debut_Annee = DateSerial(Annee, 1, 1) - Jour + 7
        End If
        Lundi = Debut_Annee + ((Num_Semaine - 1) * 7)
    End Function 

    Sub Test()
    Dim monLundi As Date
        'retourne la date du lundi de la semaine 14 de 2015
        monLundi = Lundi(14, 2015)
        MsgBox monLundi
    End Sub