VB常用算法10统计加密字符处理

1、.VB常用算法-字符处理加密与统计1、加密解密 最简单的加密方法是：将每个字母加一序数，例如5，这时： “AF,a f,B G,b gY D, y d,Z E, z e 解密是加密的逆操作。 界面如右： 代码如下： Option ExplicitPrivate Sub Command1_Click Dim strInput$, Code$, Record$, c As String * 1 Dim i%, length%, iAsc% strInput = Text1.Text length = LenTrimstrInput Code = "" For i = 1 To

2、length c = MidstrInput, i, 1 Select Case c Case "A" To "Z" iAsc = Ascc + 5 If iAsc > Asc"Z" Then iAsc = iAsc - 26 Code = Code & ChriAsc Case "a" To "z" iAsc = Ascc + 5 If iAsc > Asc"z" Then iAsc = iAsc - 26 Code = Code & ChriA

3、sc Case Else Code = Code & c End Select Next i Text2.Text = CodeEnd SubPrivate Sub Command3_Click Text1.Text = "" Text2.Text = "" Text3.Text = "" Text1.SetFocusEnd Sub 2、统计 问题提出 统计字符或者数字出现的次数。 算法说明 以字符统计为例，设根本问题如下： 请统计一段文本中英文字母在文本中出现的次数。不区分大小写 如：I am a student.

4、 得到： A:2 d:1 e:1 I:1 m:1 n:1 s:1 t:2 u:1 分析： 由于不区分大小写，因此可定义一个大小为26下标：025的数组，每个元素依次记录A、B、CZ字母出现的次数。 A0存放字母a出现的次数 A1存放字母b出现的次数 A2存放字母c出现的次数 A3存放字母d出现的次数 譬如：aabdc ，那么A0=2，A1=1，A2=1，A3=1 代码如下： Option Explicit Private Sub Command1_Click Dim i As Integer, j As Integer Dim zimu25 As Integer Dim allStr As S

5、tring Dim aStr As String allStr = UCaseText1.Text For i = 1 To LenText1.Text aStr = MidallStr, i, 1 If aStr >= "A" And aStr <= "Z" Then zimuAscaStr - Asc"A" = zimuAscaStr - Asc"A" + 1 End If Next i For i = 0 To 25 If zimui <> 0 Then j = j + 1 Text2

6、.Text = Text2.Text & Chri + Asc"A" & ":" & strzimui & " " If j Mod 5 = 0 Then Text2.Text = Text2.Text & Chr13 & Chr10 End If Next i End Sub  解题技巧 纯熟运用字符处理函数，对于一些数论题，譬如逆序数等也可将数字通过CStr函数转换为字符后，利用字符处理函数来解题。 3、实战练习1 补充代码2003秋二8 下面程序的功能是统计文件中英文字母

7、不区分大小写出现的个数。 Option Base 1Private Sub Command1_Click Dim alpha26 As Integer, n As Integer Dim i As Integer, s As String Open App.Path & "lx.txt" For Input As #11 Do While Not EOF11 s = 1 s = UCases If s >= "A" And s <= "Z" Then n = 2 alphan = alphan + 1 End If

8、 Loop For i = 1 To 26 If alphai <> 0 Then List1.AddItem Chri + 64 & ":" & CStralphai End If Next i CloseEnd Sub 2 补充代码2000秋二6 下面程序的功能是：统计当前盘当前文件夹中的顺序文件data.txt中共有多少个单词，约定连续出现的字母定义为一个单词。 Option ExplicitPrivate Sub command1_Click Dim Char As String, St As String, Tem As String Dim Idx As Integer, Js As Long, Flen As Long Dim F As Boolean, W As String * 1 1 Flen = LOF10 St = InputFlen, #10 Js = 1 Do While Js <= Flen + 1 W = MidSt, Js, 1 If 2 Then Tem = Tem + W F = True ElseIf F = True Then Idx = Idx + 1 ReDim Preserve CharIdx