Dim tabel() As Tabellendat
Public Function Zelle(Row As Integer, Col As Integer, Tabelle As Tabellendat) _
  As Integer
    Zellle = -1
    For a = 0 To UBound(Tabelle)
        If Tabelle(a).Col = Col And Tabelle(a).Row = Row Then
            Zelle = a
        End If
    Next a
End Function

c = Zelle(.Row, .Col, tabel())