加密.frm

蒋加伏主编VB程序设计第四版PPT及全部课本源码 北京邮电大学出版社 Visual Basic 程序设计教程（第四版） 主编 蒋加伏 张林峰 找了好久的（不带密码的）

VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "例[8-14]加密"
   ClientHeight    =   2235
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   4410
   LinkTopic       =   "Form1"
   ScaleHeight     =   2235
   ScaleWidth      =   4410
   StartUpPosition =   3  '窗口缺省
   Begin VB.TextBox txtRecode 
      Height          =   495
      Left            =   1178
      TabIndex        =   5
      Top             =   1590
      Width           =   3135
   End
   Begin VB.CommandButton cmdRecode 
      Caption         =   "解密"
      Height          =   495
      Left            =   98
      TabIndex        =   4
      Top             =   1590
      Width           =   975
   End
   Begin VB.TextBox txtCode 
      Height          =   495
      Left            =   1178
      TabIndex        =   3
      Top             =   870
      Width           =   3135
   End
   Begin VB.CommandButton cmdcode 
      Caption         =   "加密"
      Height          =   495
      Left            =   98
      TabIndex        =   2
      Top             =   870
      Width           =   975
   End
   Begin VB.TextBox txtInput 
      Height          =   495
      Left            =   1178
      TabIndex        =   1
      Top             =   150
      Width           =   3135
   End
   Begin VB.Label Label1 
      Caption         =   "输入字符串"
      Height          =   495
      Left            =   98
      TabIndex        =   0
      Top             =   270
      Width           =   1215
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Private Sub cmdcode_Click()         '加密
  Dim strInput$, Code$, Record$, c As String * 1
  Dim i%, length%, iAsc%
  strInput = txtInput.Text
  length = Len(RTrim(strInput)) '去掉字符串右边的空格，求真正的长度
  Code = ""
  For i = 1 To length
    c = Mid$(strInput, i, 1)    '取第i个字符
    Select Case c
      Case "A" To "Z"           '大写字母加序数3加密
        iAsc = Asc(c) + 3
        If iAsc > Asc("Z") Then iAsc = iAsc - 26 '加密后字母超过Z
        Code = Code + Chr$(iAsc)
      Case "a" To "z"
        iAsc = Asc(c) + 3       '小写字母加序数3加密
        If iAsc > Asc("z") Then iAsc = iAsc - 26 '加密后字母超过z
        Code = Code + Chr$(iAsc)
      Case Else                 '当第i个字符为其它字符时不加密
        Code = Code + c
    End Select
  Next i
  txtCode.Text = Code           '显示加密后的字符串
End Sub