计算机等级考试二级VB常用算法SFA.doc

1求任意自然数n的阶乘：方法一 Do循环法S=1For I=1 To N S=S*INext I方法二 For循环S=1：T=1Do While T=5S=S*TT= T +1Loop2闰年判断Y = Text1.TextIf (Y Mod 4 = 0 And Y Mod 100 0) Or Y Mod 400 = 0 ThenMsgbox Y & 是闰年ElseMsgbox Y & 不是闰年End If3求两个自然数m、N的最大公约数hmax和最小公倍数hminM=Text1.Text : N=Text2.Text M和n可通过其他途径赋值mn=M*N 暂存m和n的乘积，以便后面算最小公倍数If MN Then T=M ：M=N ：N=TEnd IfR=M Mod NDo While R0M=NN=RR=M Mod NLoopHmax=NHmin=Mn/Hmax4. 素数判断素数判断方法一 提前退出法N=Inputbox( “输入=3的正整数”)For I=2 To N1 或sqr(N) ，提前退出法If (N Mod I =0) Then Exit ForNext IIf IN-1 Then Print N; “是素数”ElsePrint N; “不是素数”End If方法二 标志法N=Inputbox( “输入一个=3的正整数”)End IfF=0 F也可用逻辑型变量，标志法For I=2 To N1 或sqr(N)If (N Mod I =0) Then F=1Next IIf F=0 Then Print N; “是素数”ElsePrint N; “不是素数”End IfText2.Text = m = Val(Text1.Text) If m 0 Then 正数Text2.Text = 1ElseIf m = A And Ucase(Temp) = Z And Newword = False Then Wordnum = Wordnum + 1Newword = TrueEnd IfNext IText2.Text = Wordnum方法二 根据相邻两字符特征判断Dim A$, Tempf$, Tempb$Dim N%, Wnum%, I%A = Text1.Text A = Ltrim(Text1.Text)Wnum = 0N = Len(A)For I = 1 To N - 1 避免超出范围Tempf = Mid(A, I, 1)Tempb = Mid(A, I + 1, 1)If Wnum = 0 And Tempf Then 对第一个单词特殊处理Wnum = Wnum + 1Elseif Tempf = And Tempb ThenWnum = Wnum + 1End IfNext IText2.Text = Wnum5找出二维矩阵中的最大元素、最小元素及其所在位置Dim Dmax%, Rowmax%, Colmax% 最大值、所在行、所在列Dim Dmin%, Rowmin%, Colmin% 最小值、所在行、所在列Dim I%, J%Dmax = A(1, 1): Rowmax = 1: Colmax = 1 假设a(1, 1)最大,记录位置Dmin = A(1, 1): Rowmin = 1: Colmin = 1 假设a(1, 1)最小,记录位置For I = 1 To Ubound(A, 1) 第一维下标范围For J = 1 To Ubound(A, 2) 第二维下标范围找最大If Dmax A(I, J) ThenDmin = A(I, J)Rowmin = IColmin = JEnd IfNext JNext IPrint 最大元素:; Dmax; ,它在第; Rowmax; 行,第; Colmax; 列Print 最小元素:; Dmin; ,它在第; Rowmin; 行,第; Colmin; 列产生n个10，100范围内互不相同的数据Dim T() As Integer 过程级动态数组Dim N As IntegerForm1.ClsN = Inputbox(输入一个值)Redim T(N)RandomizeFor I = 1 To NT(I) = Int(Rnd * 91 + 10) 保证与前面的数据不等For J = 1 To I - 1If T(I) = T(J) Then I = I - 1: Exit ForNext J Next I6一维数组的排序（10个数据，升序为例）方法一 比较交换法（经典排序法）（输出可同时进行）外重循环i 控制比较的轮数提供每轮参照元素下标（1 To N-1） 内重循环j 要与参照元素比较的元素的下标(I+1 To N)For I = 1 To 9 轮数及参照元素下标For J = I + 1 To 10 与参照元素比较的元素下标 If A(I) A(J) ThenT = A(I)A(I) = A(J)A(J) = TEnd IfNext JNext I方法二 选择交换法（输出可同时进行）内、外重循环的含义和作用与比较交换法相同For I = 1 To 9K = I K记录较小元素的下标For J = I + 1 To 10If A(K) A(J) Then K = JNext JIf K I ThenT = A(I) : A(I) = A(K) : A(K) = TEnd IfNext I方法三 冒泡法排序（输出独立进行）外重循环i 控制比较的轮数（1 To N-1 ） 决定各轮要参与比较的元素的范围 内重循环j 提供每轮要与后面相邻元素进行比较的元素的下标(1to N-I )For I = 1 To 9 10 To 2 Step -1For J = 1 To 10 I 1 To I-1If A(J) A(J + 1) Then 相邻元素比较T = A(J): A(J) = A(J + 1): A(J + 1) = TEnd IfNext JNext I方法四 插入法排序绝对位置插入法：(结果的输出必须独立进行)第一重循环i 要决定位置的元素的下标( 2N-1)第二重循环j 第i个元素要插入的有序数列(1I-1)第三重循环k 当a(I)A(J)时, 后移的元素(I-1J) For I = 2 To 10N = A(I) 暂存a(I),避免冲掉For J = 1 To I - 1If N A(I-1), N原本就放在a(I)相对位置插入法：(结果的输出必须独立进行)外重循环i 要决定位置的元素的下标( 2N-1)内重循环j 第i个元素要插入的有序数列下标范围(I-1 1)For I = 2 To 10N = A(I)For J = I - 1 To 1 Step 1 反向If N A(J) ThenA(J + 1) = A(J)A(J) = NElseA(J + 1) = N 本句可不要Exit ForEnd IfNext JNext I7有序数列的插入操作（假设原数组中已存放10个数据）绝对位置插入法：S = Val(Inputbox(输入1545之间的整数)A(11) = S 提前放入For I = 1 To 10If S = A And D = Z ThenJ = Asc(D)A(J) = A(J) + 1 对应数组元素加1End IfNext IFor I = 65 To 90 输出字母及其出现的次数If A(I) 0 Then 表明对应字母出现了K = K + 1 用于控制输出格式Picture1.Print Chr$(I); =; A(I); ;If K Mod 9 = 0 Then Picture1.Print 每行输出9个End IfNext J10二分法查找（前提原数组有序，设原数组已按升序排序）Dim N%Dim Bot%, Mid%, Top%, Find As BooleanN = Val(Inputbox(请输入要查找的数据)Bot = 1: Top = 10 Find = False 是否找到的标志Do 三个分支Mid = Int(Bot + Top) / 2)If N = A(Mid) ThenFind = TrueMsgbox 在a( & Mid & ) & 找到数据 & NExit Do 可不要Elseif N A(Mid) ThenBot = Mid + 1End IfLoop Until Find = True Or Bot TopIf Find = False Then Msgbox 没找到 & N & .11字符串的加密、解密问题加密解密问题.加密规律: 小写字母: A-D,B-EW-Z,X-A,Y-B,Z-C大写字母: A-D,B-EW-Z,X-A,Y-B,Z-C其它字符不变。解密时，基于上述加密规律。加密Private Sub Command1_Click()Dim Sm1 As String, Mm1 As String, Temp1 As String * 1Dim N%, I%Sm1 = Text1.TextN = Len(Sm1)Mm1 = For I = 1 To NTemp1 = Mid(Sm1, I, 1)Select Case Temp1Case A To W, A To WTemp1 = Chr(Asc(Temp1) + 3)Case X To Z, X To ZTemp1 = Chr(Asc(Temp1) + 3 - 26)End SelectMm1 = Mm1 & Temp1Next IText2.Text = Mm1End Sub解密Private Sub Command2_Click()Dim Sm2 As String, Mm2 As String, Temp2 As String * 1Dim M%, J%Mm2 = Text3.TextM = Len(Mm2)Sm2 = For J = 1 To MTemp2 = Mid(Mm2, J, 1)Select Case Temp2Case D To Z, D To ZTemp2 = Chr(Asc(Temp2) - 3)Case A To C, A To CTemp2 = Chr(Asc(Temp2) - 3 + 26)End SelectSm2 = Sm2 & Temp2Next JText4.Text = Sm2End Sub14. 字符的分类统计字符统计问题：有一段文字, 要求统计其中的大写字母、小写字母、数字字符、其它字符各有多少个。 Dim K$, Temp$Dim N%, I%Dim Nn%, Nu%, Nl%, Ne%K = Text1.TextN = Len(K)For I = 1 To NTemp = Mid(K, I, 1)If Temp = 0 And Temp = A And Temp = A And Temp = Z ThenNl = Nl + 1ElseNe = Ne + 1End IfNext I要实现多行输出,Text2.Multiline必须为trueText2.Text = Text2 & 数字 & Nn & 个 & Chr(13) & Chr(10) _& 大写字母 & Nu & 个 & Chr(13) & Chr(10) _& 小写字母 & Nl & 个 & Chr(13) & Chr(10) _& 其他字符 & Ne & 个15.密码检测问题Private Sub Form_Load()Text1.Maxlength = 6Text1.Passwordchar = *Const Pas=321abc 在此处定义是否行得通,常量的作用域问题?End SubPrivate Sub Command1_Click()Dim Enterpas As String, I As IntegerStatic N%Const Pas = 321abc 假设的正确密码 L: Enterpas = Text1.Text 实际输入密码If Enterpas = Pas ThenMsgbox 密码正确EndElseI = Msgbox(密码错误, Vbretrycancel + Vbexclamation