Question

我正在尝试模仿Caesar Cipher加密。问题是每当我输入“wxyz”时（移位3）输出为“z {|}”。但预期的输出应该是“zabc”。

任何人都知道要添加什么？

Public Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
            Dim plaintext As String = TextBox1.Text
            Dim charArray() As Char = plaintext.ToCharArray
            Dim shift = TextBox2.Text
            Dim character As String
            Dim temp As String
            TextBox3.Text = ""



            If shift <> "" And IsNumeric(shift) Then
                If plaintext = "" Then
                    MsgBox("Please input some plain text")
                    Exit Sub
                End If
                If shift > 26 Then
                    MsgBox("Maximum shifts reached. Limit is 26!!")
                    Exit Sub
                End If
                For loope = 0 To charArray.Length - 1 Step +1
                    temp = charArray(loope)

                    character = Chr(Asc(temp) + shift)

                    TextBox3.Text += character


                Next
                Exit Sub
            Else
                MsgBox("Input numbers only!!")
            End If


        End Sub

Answer 1

当您移动Ascii代码时，您应该验证它不会超过122，这是字符＆＃34; z＆＃34;的Ascii代码。如果你超越这一点，你会得到标点符号，符号和那些东西。 Google＆＃34; ASCII表＆＃34;你可以自己轻松地看到它。

所以，为了解决你的问题，如果你在转移后获得的Ascii代码大于122，你应该回去再次从97开始，这是＆＃34; a＆＃34;的ascii。

所以，而不是：

            For loope = 0 To charArray.Length - 1 Step +1
                temp = charArray(loope)
                character = Chr(Asc(temp) + shift)
                TextBox3.Text += character
            Next

您应该执行类似

的操作

            For loope = 0 To charArray.Length - 1 Step +1
                temp = charArray(loope)
                character = Chr(Asc(temp) + shift)
                ' You substract 26, the whole length of the alphabet
                If character > 122 Then
                   character = character - 26 
                End If
                TextBox3.Text += character
            Next

如果shift大于26，则不确定这是否稳定，但无论如何你已经检查了它的值，所以它应该有效。

VB - Caesar Cipher仿真

1 个答案: