Visual Basic 2010 For ..至陈述

Question

公开课表格1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim password As String, ch As Char
    Dim i As Integer
    Dim valid As Boolean = False
    While valid = False
        password = InputBox("Please enter  your password")
        For i = 0 To password.Length - 1
            ch = password.Chars(i)
            If Not Char.IsLetterOrDigit(ch) Then
                valid = True
                Exit For
            End If
        Next
        If valid Then
            MsgBox("Your new password will be activated immediately")
        Else
            MsgBox("your password must contain at least one special symbol")
        End If
    End While
End Sub

大家好，此程序将检查密码中是否有符号，我的问题在陈述中（ For i = 0 To password.Length - 1 ），其有关（-1）为什么我们写-1，i理解一切除了-1，谢谢

Answer 1

是的，我知道了，你是对的。 这是因为vb从0开始计数，所以如果我写1234，这意味着vb 12345，然后我们应该将-1删除最后一位数字，然后将1234作为结果。 谢谢汉斯·帕桑特