Question

我正在编写一个基本上通过二维数组运行的应用程序，并将数组中每个项的值乘以2，由于某种原因，外部循环每次重复时都会执行两次。为什么会这样？

Private Sub btnCalc_Click(sender As Object, e As EventArgs) Handles btnCalc.Click
    ' multiplies each array element by 2 and then displays the results in a list box

    Dim intInventory(,) As Integer = {{45, 67}, {2, 4}, {50, 7}, {9, 8}}

    For indexOuter As Integer = 0 To intInventory.GetUpperBound(0)
        intInventory(indexOuter, 0) *= 2
        lstInventory.Items.Add(intInventory(indexOuter, 0))

        For indexInner As Integer = 0 To intInventory.GetUpperBound(1)
            intInventory(indexOuter, indexInner) *= 2
            lstInventory.Items.Add(intInventory(indexOuter, indexInner))
        Next
    Next

End Sub

Answer 1

不要这样做：

    intInventory(indexOuter, 0) *= 2
    lstInventory.Items.Add(intInventory(indexOuter, 0))

因为第一次迭代（indexInner=0）覆盖了它：

    For indexInner As Integer = 0 To intInventory.GetUpperBound(1)
        intInventory(indexOuter, indexInner) *= 2
        lstInventory.Items.Add(intInventory(indexOuter, indexInner))

外嵌套循环返回值两次？

1 个答案: