设计一个加密程序，加密规则为明文后移4个字符即为密文，例如“ABCD”加密后密文是“EFGH”、“WXYZ”加密后密文是“ABCD”。利用Inputbox接收输入的明文，将明文、密文显示在窗体上。
没啥好
镇楼
的了，将就一下

我可以做

然后呢

Option Explicit
Private Sub Form_Load()
Dim i As Integer
Dim btData() As Byte
btData = InputBox("请输入明文：", "提示")
For i = 0 To UBound(btData)
If btData(i) >= 65 And btData(i) <= 90 Then 'A～Z
If btData(i) + 4 <= 90 Then
btData(i) = btData(i) + 4
Else
btData(i) = btData(i) - 22
End If
ElseIf btData(i) >= 97 And btData(i) <= 122 Then 'a～z
If btData(i) + 4 <= 122 Then
btData(i) = btData(i) + 4
Else
btData(i) = btData(i) - 22
End If
End If
Next
Debug.Print "密文：" & CStr(btData)
End Sub

Option Explicit
Private Const Password = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
Private Sub Command1_Click()
Dim b As Integer, a As String, c As String, d As Integer
a = InputBox("请输入", "输入")
d = Len(a)
If d <> 4 Then
MsgBox "请输入四位", 16, "提示"
Else
If a = "WXYZ" Then
Label1.Caption = "明文:WXYZ"
Label2.Caption = "密文:ABCD"
Else
b = InStr(Password, a)
c = Mid(Password, b + 4, 4)
Label1.Caption = "明文:" + a
Label2.Caption = "密文:" + c
End If
End If
End Sub

Private Function encodeCodes(sIn As String) As String
Dim i As Integer
Dim tmp() As Byte
tmp = sIn
For i = 0 To UBound(tmp) Step 2
tmp(i) = tmp(i) + 4
If tmp(i) > 90 And tmp(i) < 97 Or tmp(i) > 122 Then
tmp(i) = tmp(i) - 26
End If
Next
encodeCodes = tmp
End Function

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