Private Sub GetPrimOptimiert()
Dim i As Long, lBisZahl As Long
Dim lCurrentPrim As Long
Dim lEndeZahl As Long
Dim lStart As Long, lEnde As Long
Dim sOut As String
Dim bitPrim As clsBitArray
Dim lS As Long, lE As Long
Dim lStep As Long
Dim lTemp As Long, lTemp2 As Long
 
 
Set bitPrim = New clsBitArray
 
 
  lBisZahl = Text1.Text - 1
 
  lStart = GetTickCount
 
  ' Array dimensionieren
  lTemp = CLng(lBisZahl / 2)
  If lBisZahl Mod 2 = 1 Then lTemp = lTemp + 1
  bitPrim.Bits = lTemp
 
 
  lEndeZahl = (lBisZahl + 1) / 2
  For lCurrentPrim = 3 To lEndeZahl Step 2
 
    If bitPrim.Bit(GetIndex(lCurrentPrim)) = False Then
      lStep = lCurrentPrim
      lTemp = lBisZahl / 2
      lTemp2 = GetIndex(lCurrentPrim)
 
      For i = lTemp2 + lStep To lTemp Step lStep
        bitPrim.Bit(i) = True
      Next i
 
    End If
 
  Next lCurrentPrim
 
  lEnde = GetTickCount
  sOut = "Dauer der Berechnung: " & lEnde - lStart & "ms" & vbCrLf
 
  MsgBox sOut
End Sub
 
Private Function GetIndex(Zahl As Long) As Long
  GetIndex = Zahl \ 2 + 1
 
End Function