'teilweise von Winfried Radner
'e-mail: Wolf.W.Radzinski@onlinehome.de

Sub prim()
start = Timer
Columns("B:B").Select
Selection.ClearContents
Range("A1").Select
  a = Range("a1").Value
  e = Range("a2").Value
z = 1
If a <= 2 Then
  If a = 2 Then
  Range("b1").Value = 2
  z = 2
  End If
If a = 1 Then
Range("b1").Value = 1
Range("b2").Value = 2
z = 3
End If
  If a = 0 Then
  Range("b1").Value = 0
  Range("b2").Value = 1
  Range("b3").Value = 2
  z = 4
  End If
End If
For i = a To e
  For ii = 2 To (i - 1)
  p = i / ii - Fix(i / ii)
  If p = 0 Then Exit For
  Next ii
If p = 0 Then GoTo raus
Range("b" & z).Value = i
Application.StatusBar = i
z = z + 1
raus:
Next i
Cells(3, 1).Value = Timer - start
End Sub


Sub prim2()
start1 = Timer
Columns("C:C").Select
Selection.ClearContents
Range("A1").Select
  a = Range("a1").Value
  e = Range("a2").Value
z = 1
If a <= 2 Then
  If a = 2 Then
  Range("c1").Value = 2
  z = 2
  End If
If a = 1 Then
Range("c1").Value = 1
Range("c2").Value = 2
z = 3
End If
  If a = 0 Then
  Range("c1").Value = 0
  Range("c2").Value = 1
  Range("c3").Value = 2
  z = 4
  End If
End If

  If ((a / 2) - Fix(a / 2)) = 0 Then a = a + 1
  If ((e / 2) - Fix(e / 2)) = 0 Then e = e - 1
  'die einzige gerade Primzahl ist die ZWEI!
  
  '3 wird extra behandelt
  If a <= 3 Then
    Range("c" & z).Value = 3
    Application.StatusBar = 3
    z = z + 1
    If e > 5 Then a = a + 2
  End If
  
For i = a To e Step 2
  'prüfe nur noch ungerade Zahlen! bei geraden Zahlen ist prüfen sinnlos!
  
  iii = Fix(Sqr(i) + 1)
  'und jeweils nur bis zur Wurzel prüfen (wichtig! da besonders zeitkritisch)
  
  For ii = 3 To iii Step 2
  'auch hier muß ich nicht durch gerade Zahlen teilen!
  
  p = i / ii - Fix(i / ii)
  If p = 0 Then Exit For
  Next ii
  
If p = 0 Then GoTo raus
Range("c" & z).Value = i
Application.StatusBar = i
z = z + 1
raus:
Next i
Cells(4, 1).Value = Timer - start1
End Sub

Sub teste_auf_gleich()
Columns("D:D").Select
Selection.ClearContents
Columns("b:b").Select
x = 0
For Each z In Selection
If IsEmpty(z) Then Exit For
y = Selection(z.Row).Offset(0, 1)
If z <> y Then
    Selection(z.Row).Offset(0, 2) = "!!!!!"
    x = x + 1
End If
Range("A8").Value = x
Next

End Sub


Private Sub Worksheet_SelectionChange(ByVal Target As Excel.Range)
   If Target.Address = "$A$5" Then prim
   If Target.Address = "$A$6" Then prim2
   If Target.Address = "$A$7" Then teste_auf_gleich
   
End Sub