外壳排序算法

Question

我正在尝试使用shell排序算法实现一个数组。单击按钮后，程序将对数组进行排序，并将每个元素输出到列表框。但是，第一项输出始终为0。我已经包含了我的一段源代码和下面表格的一张照片；

 Dim randGen As New Random()
    Dim unstArray() As Integer
    Dim unstArrayCopy() As Integer
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 'Generates random number to save in array.
        Dim i As Integer = CInt(TextBox1.Text)
        ReDim unstArray(i)
        ReDim unstArrayCopy(i)
        For x = 0 To i
            unstArray(x) = randGen.Next(1, 10001)
        Next
        Array.Copy(unstArray, unstArrayCopy, i)
    End Sub

 Private Sub ShllSrtBtn_Click(sender As Object, e As EventArgs) Handles shllSrtBtn.Click
        shellsort(unstArrayCopy, unstArrayCopy.GetUpperBound(0))
    End Sub

    Sub shellsort(ByRef shellSort() As Integer, ByVal max As Integer)
        Dim stopp%, swap%, limit%, temp%, k%
        Dim x As Integer = CInt((max / 2) - 1)
        Do While x > 0
            stopp = 0
            limit = max - x
            Do While stopp = 0
                swap = 0
                For k = 0 To limit
                    If shellSort(k) > shellSort(k + x) Then
                        temp = shellSort(k)
                        shellSort(k) = shellSort(k + x)
                        shellSort(k + x) = temp
                        swap = k
                    End If
                Next k
                limit = swap - x
                If swap = 0 Then stopp = 1
            Loop
            x = CInt(x / 2)
        Loop
        For i = 0 To shellSort.GetUpperBound(0)
            ListBox1.Items.Add(shellSort(i))
        Next i
    End Sub

​

​

Answer 1

问题出在这里：

    ReDim unstArray(i)
    ReDim unstArrayCopy(i)

在VB中，当你初始化一个数组时，你必须给它提供你想要使用的最大索引，而不是像在C#这样的其他语言中所期望的数组长度。

因此，您的代码创建了一个长度为i+1的数组，但是在填充该数组时，您只能从0循环到i。因此索引i处的最后一个元素将始终为零。

您应该将这些行中的初始化器设置为i-1。

VB Array Reference