Module Module1
    Public anfZahl As Integer
    Public endZahl As Integer
    Public zahlen(0) As Integer
    Public zaehler As Integer = 0

    Sub Main()
        Console.Write("Bitte den Anfangswert des Wertebereichs eingeben: ")
        anfZahl = Console.ReadLine
        Console.Write("Bitte den Endwert des Wertebereichs eingeben: ")
        endZahl = Console.ReadLine
        Console.WriteLine()

        Dim prim(endZahl + 1) As Boolean
        For i As Integer = 0 To endZahl + 1
            prim(i) = True
        Next
        For j As Integer = 2 To endZahl
            prim(j) = False
        Next

        primSuche(prim)

        For z As Integer = 0 To zahlen.Length - 2
            If zahlen(z) + 2 = zahlen(z + 1) Then
                Console.WriteLine(zahlen(z) & " - " & zahlen(z + 1))
            End If
        Next

        Console.ReadLine()
    End Sub

    Public Sub primSuche(ByRef prim() As Boolean)
        For i As Integer = 2 To endZahl
            If Not prim(i) Then
                ReDim Preserve zahlen(zaehler)
                zahlen(zaehler) = i
                zaehler += 1
                For j As Integer = i * i To endZahl Step i
                    prim(j) = True
                Next
            End If
        Next
    End Sub

End Module