Private Function CheckLines3(ByVal infile As String, ByVal outfile As String, _
               ByVal PrüfSpalte As Integer) As Boolean
 
On Error GoTo fehler
Dim lines() As String, ak%, i%, k%, fieldsv$(), fieldsp$()
If Not ReadLines(infile, lines) Then CheckLines3 = False: Exit Function
 
Dim written() As Boolean
ReDim written(UBound(lines)) As Boolean
 
ak = FreeFile
Open outfile For Output As #ak
For i = 1 To UBound(lines)
   fieldsv = Split(lines(i - 1), ",")
   fieldsp = Split(lines(i), ",")
 
   If CInt(Trim(fieldsv(PrüfSpalte))) <> _
       CInt(Trim(fieldsp(PrüfSpalte))) Then
       If Not written(i - 1) Then
           Print #ak, lines(i - 1)
       End If
       If Not written(i) Then
          Print #ak, lines(i)
          written(i) = True
       End If
       If i < UBound(lines) Then
          written(i + 1) = True
          Print #ak, lines(i + 1)
       End If
   End If
Next i
Close #ak
CheckLines3 = True
Exit Function
 
fehler:
Close #ak
CheckLines3 = False
End Function