Question

vb 数组下标越界

Private Sub Command1_Click()
Text1.Text = ""
Dim S As Long, i As Long
Dim A()
Do
ReDim Preserve A(S)
A(S) = InputBox("请输入字符串，输入空串时结束", "输入")
S = S + 1
Loop Until A(S - 1) = ""
For i = 0 To S - 2
Text1.Text = Text1.Text & "第" & CStr(i + 1) & "个是：" & CStr(A(i)) & " "
Next i
Erase A
End Sub
为什么把Loop Until A(S - 1) = "" 改成Loop Until A(S) = "" 就提示下标越界？

Answer 1

咱分析分析这么几句话。
Do
ReDim Preserve A(S)
A(S) = InputBox("请输入字符串，输入空串时结束", "输入")
S = S + 1
Loop Until A(S - 1) = ""
运行到 ReDim Preserve A(S)，数组最大下标是S，假设是5。
运行到A(S) = InputBox("请输入字符串，输入空串时结束", "输入")，这句无关大碍，略。
运行到S = S + 1，注意此S非彼S了，比刚才大了1，按刚才的假设，是6.
如果按你的修改，运行到Loop Until A(S) = "" ，你想想，S大了1是6，所以A(S) 根本没有数据和他对应，A(6)根本就是空的。当然下标越界啦。