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VisualBasic Quellcode

Module Module1
 
    'liste mit 15 Elementen, welches später sortiert werden soll deklarieren
    Dim list_to_be_sorted(15) As Integer
 
    'Hilfsroutine um ein Integer-Array in der Konsole auszugeben
    Sub print_list(ByRef liste() As Integer)
        For Each element In liste
            Console.Write(element.ToString & " ")
        Next
        Console.WriteLine("-")
    End Sub
 
    'Hilfsroutine um eine Liste von Integern in der Konsole auszugeben
    Sub print_list(ByRef liste As List(Of Integer))
        For Each element In liste
            Console.Write(element.ToString & " ")
        Next
        Console.WriteLine("-")
    End Sub
 
    'Methode um ein liste mit Zufallswerten zu initialisieren
    Sub initialize_list(ByRef liste() As Integer)
        'Zufallsgenerator initialisieren
        Dim r As New Random(System.DateTime.Now.Millisecond)
        'Jedem Element der Schleife einen zufälligen Wert zuweisen
        For i As Integer = 0 To liste.Length - 1
            'Zufallszahl zwischen 0 und 10.000 erzeugen und zuweisen
            liste(i) = r.Next(0, 10000)
        Next
    End Sub
 
    'Hilfsmethode um zwei stellen im liste zu vertauschen
    Sub swap(ByRef x As Integer, ByRef y As Integer)
        Dim tmp As Integer
        tmp = x
        x = y
        y = tmp
    End Sub
 
    'VB Implementierung des BubbleSort-Algorithmus wie er auf Wikipedia beschrieben ist: http://de.wikipedia.org/wiki/Bubblesort
    Sub bubblesort(ByRef liste() As Integer)
        Dim n As Integer = liste.Length
        Dim swapped As Boolean
        Do
            swapped = False
            For i As Integer = 0 To n - 2
                If (liste(i) > liste(i + 1)) Then
                    swap(liste(i), liste(i + 1))
                    swapped = True
                End If
            Next
            n = n - 1
        Loop While n > 1
    End Sub
 
    'VB Implementierung des Insertionsort-Algorithmus wie er auf Wikipedia beschrieben ist: http://de.wikipedia.org/wiki/Insertionsort
    Sub insertionsort(ByRef liste() As Integer)        '        
        Dim val, j As Integer
        For i As Integer = 1 To liste.Length - 1
            val = liste(i)
            j = i
            While (j > 0 AndAlso liste(j - 1) > val)
                liste(j) = liste(j - 1)
                j = j - 1
                liste(j) = val
            End While
        Next
    End Sub
 
 
    ' MergeSort implementation
    Sub MergeSort(ByRef szArray As List(Of Integer), ByVal nLower As Integer, ByVal nUpper As Integer)
 
        ' Check for array size
        Dim szSwap As String
        If (nUpper - nLower) = 1 Then
 
            ' Swap strings if necessary
            If szArray(nLower).CompareTo(szArray(nUpper)) > 0 Then
                szSwap = szArray(nLower)
                szArray(nLower) = szArray(nUpper)
                szArray(nUpper) = szSwap
            End If
 
        ElseIf (nUpper - nLower) > 1 Then
 
            ' Sort each half and merge
            MergeSort(szArray, nLower, (nLower + nUpper) / 2)
            MergeSort(szArray, (nLower + nUpper) / 2 + 1, nUpper)
            Merge(szArray, nLower, (nLower + nUpper) / 2 + 1, nUpper)
 
        End If
 
    End Sub
 
    Sub Merge(ByRef szArray As List(Of Integer), ByVal nLower As Integer, ByVal nMiddle As Integer, ByVal nUpper As Integer)
 
        Dim nIndex As Integer
        Dim szBuffer As New List(Of Integer)()
 
        Dim i, j As Integer
        i = nLower
        j = nMiddle
        While i < nMiddle And j <= nUpper
            If (szArray(i).CompareTo(szArray(j)) < 0) Then
                szBuffer.Add(szArray(i))
                i = i + 1
            Else
                szBuffer.Add(szArray(j))
                j = j + 1
            End If
 
        End While
 
        While i < nMiddle
            szBuffer.Add(szArray(i))
            i = i + 1
        End While
        While j <= nUpper
            szBuffer.Add(szArray(j))
            j = j + 1
        End While
 
        nIndex = 0
        For i = nLower To nUpper
            szArray(i) = szBuffer(nIndex)
            nIndex = nIndex + 1
        Next i
 
    End Sub
 
 
    Public Function QuickSort(ByVal list As List(Of Integer)) As List(Of Integer)
        If list.Count < 1 Then Return list
        Dim Smaller As New List(Of Integer)
        Dim Larger As New List(Of Integer)
        Dim pt As Integer = 0
        QuickSort = New List(Of Integer)
        Dim pv As Integer = list(Int(Rnd() * list.Count))
        For i As Integer = 0 To list.Count - 1
            Select Case list(i)
                Case Is = pv
                    pt += 1
                Case Is < pv
                    Smaller.Add(list(i))
                Case Is > pv
                    Larger.Add(list(i))
            End Select
        Next
        QuickSort.AddRange(QuickSort(Smaller))
        While pt > 0
            QuickSort.Add(pv)
            pt -= 1
        End While
        QuickSort.AddRange(QuickSort(Larger))
    End Function
 
    Sub Main()
        Dim al As List(Of Integer) = New List(Of Integer)
        initialize_list(list_to_be_sorted)
        al.AddRange(list_to_be_sorted)
 
        print_list(list_to_be_sorted)
 
        'bubblesort(liste_to_be_sorted)
        'insertionsort(liste_to_be_sorted)
        'MergeSort(al, 0, list_to_be_sorted.Length - 1)
        al = QuickSort(al)
 
        print_list(al)
        'print_list(list_to_be_sorted)
        Console.ReadKey()
 
    End Sub
 
End Module