Option Explicit
 
Public ATage As Integer, ATM As Integer
'Anzahl Tage im Monat
Public Sub AnzahlTageMonat()
 
    ATage = Choose(Month(DatumEnde), 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, _
      30, 31)
 
    If ATage = 28 Then
        ' Schaltjahr
        Dim j As Integer
        j = Year(DatumEnde)
        If (j Mod 4) = 0 And ((j Mod 100) <> 0 Or (j Mod 400) = 0) Then ATage = 29
    End If
    ATM = ATage
 
End Sub