VB常用算法10統(tǒng)計(jì)加密字符處理

1、.VB常用算法-字符處理加密與統(tǒng)計(jì)1、加密解密 最簡單的加密方法是：將每個(gè)字母加一序數(shù)，例如5，這時(shí)： “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： 代碼如下： 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、統(tǒng)計(jì) 問題提出 統(tǒng)計(jì)字符或者數(shù)字出現(xiàn)的次數(shù)。 算法說明 以字符統(tǒng)計(jì)為例，設(shè)根本問題如下： 請(qǐng)統(tǒng)計(jì)一段文本中英文字母在文本中出現(xiàn)的次數(shù)。不區(qū)分大小寫 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： 由于不區(qū)分大小寫，因此可定義一個(gè)大小為26下標(biāo)：025的數(shù)組，每個(gè)元素依次記錄A、B、CZ字母出現(xiàn)的次數(shù)。 A0存放字母a出現(xiàn)的次數(shù) A1存放字母b出現(xiàn)的次數(shù) A2存放字母c出現(xiàn)的次數(shù) A3存放字母d出現(xiàn)的次數(shù) 譬如：aabdc ，那么A0=2，A1=1，A2=1，A3=1 代碼如下： 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  解題技巧 純熟運(yùn)用字符處理函數(shù)，對(duì)于一些數(shù)論題，譬如逆序數(shù)等也可將數(shù)字通過CStr函數(shù)轉(zhuǎn)換為字符后，利用字符處理函數(shù)來解題。 3、實(shí)戰(zhàn)練習(xí)1 補(bǔ)充代碼2003秋二8 下面程序的功能是統(tǒng)計(jì)文件中英文字母

7、不區(qū)分大小寫出現(xiàn)的個(gè)數(shù)。 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 補(bǔ)充代碼2000秋二6 下面程序的功能是：統(tǒng)計(jì)當(dāng)前盤當(dāng)前文件夾中的順序文件data.txt中共有多少個(gè)單詞，約定連續(xù)出現(xiàn)的字母定義為一個(gè)單詞。 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