VB练习题a及答案.doc

A1. 编写程序，计算并输出下面数列前n项的和 (设n=15,结果取4位小数)。 数列为： 2/1,3/2,5/3,8/5,13/8,21/13,（结果：24.5701）main: Dim a, b, t, I As Integer Dim sum, q As Single a = 1 : b = 2 : sum = 0 For I = 1 To 15 q = b / a sum = sum + q t = a a = b b = b + t Next I sum = Format(sum, #.0000) MsgBox(Str(sum)A2. 编写程序，计算并输出所有六位正整数中同时能被3和7整除的数的个数及它们的平方根的和。（结果：个数：42858 平方根和：30742714.4533428）Main:Dim n, I As Integer Dim s As Double n = 0 : s = 0 For I = 100000 To 999999 If I Mod 3 = 0 And I Mod 7 = 0 Then n = n + 1 s = s + Math.Sqrt(I) End If Next I MsgBox(个数是 + Str(n) + Chr(10) + 平方根之和是 + Str(s)A3. 编写程序，计算并输出所有6位正整数中能被6整除且其十位数不是4的数之和，并求它们中的最大数。 （结果：和:7.42508E+10 最大值：999996）Main: Dim I, max As Long Dim s As Single max = 100000 For I = 100000 To 999999 If (I Mod 6) = 0 And (I Mod 100) 10) 4 Then s = s + I If (max eps) And (I 100) I = I + 1 迭代次数统计 x1 = x2 将上次计算结果作为本次计算的初值 x2 = 2.5 - Math.Log(x1) End While If I eps) And (I 100) I = I + 1 迭代次数统计 x1 = x2 将上次计算结果作为本次计算的初值 x2 = 2.5 + Math.Log(x1) End While If I 100 Then MsgBox(函数根: + Str(x2) + 迭代 + Str(I) + 次) Else MsgBox(已迭代了100次，没有达到精度要求！) End If End SubA12 编写程序，计算并输出下面级数前n项(n=49)中奇数项的和。 s = 1*2+2*3+3*4+4*5+n*(n+1)+（结果：21450）Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.ClickDim n as integer, s as doubles = 0For n = 1 To 49 Step 2 s = s + n * (n + 1)Next nMsgbox(前50项中偶数项和S=&s)End SubA13编写程序，计算并输出所有5位正整数中能被7整除且其十位数不是7的数之和，并求它们中的最大数。 （和：6.364356E+08 最大值：99995）Dim I, max As Long Dim s As Single s = 0 max = 10000 For I = 10000 To 99999 If (I Mod 7 = 0) And (I Mod 100) 10 7) Then s = s + I If (max eps) And (Math.Abs(a - b) eps) If F(c) * F(b) 0 Then a = c If F(a) * F(c) eps) And (I 100) I = I + 1 x1 = x2 x2 = 2.5 (-x1) End While If I eps) And (I 100) I = I + 1 x1 = x2 x2 = 1.5 * Math.Sin(x1) End While If I eps) And (i 100) i = i + 1 迭代次数的统计 x1 = x2 将上次运算结果作为本次计算的初值 x2 = x1 - f(x1) / f1(x1) End While If i eps) And (Math.Abs(a - b) eps) If F(c) * F(b) 0 Then a = c If F(a) * F(c) 0 Then b = c c = (a + b) / 2 End While MsgBox(函数根为: + Str(c) + Chr(10) + 该点的函数值为 + Str(F(c) End SubA21 编写程序，统计10000到40000之间回文数的个数。（例：23732即为回文数，即正反读数据相同）（结果：300）Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim i, j, p As Integer Dim a, b, c, d, f As Integer Dim str1 As String p = 0 str1 = For i = 10000 To 40000 a = i Mod 10 b = (i Mod 100) 10 c = (i Mod 1000) 100 d = (i Mod 10000) 1000 f = i 10000 j = a * 10000 + b * 1000 + c * 100 + d * 10 + f If i = j Then str1 = str1 + Str(i) + Space(3) p = p + 1 If p Mod 12 = 0 Then str1 = str1 + Chr(10) + Chr(13) End If Next MsgBox(p) End SubA22 编写程序，求5664，144的最大公约数（48）Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim num1 As Integer Dim num2 As Integer Dim inlarge As Integer Dim insmall As Integer Dim inrem As Integer num1 = 5664 num2 = 148 If num1 num2 Then inlarge = num2 insmall = num1 Else inlarge = num1 insmall = num2 End If inrem = inlarge Mod insmall While inrem 0 inlarge = insmall insmall = inrem inrem = inlarge Mod insmall End While Label6.Text = Label3.Text + 和 + Label5.Text + 的最大公约数为： Label7.Text = Str(insmall) End SubA23从三位奇数中找出其值恰好等于该数每位数字立方和的各个数之和。（结果：931）Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim i, m, n, k As Integer Dim s As integer s = 0 For i = 101 To 999 Step 2 m = i 100 n = (i Mod 100) 10 k = i Mod 10 If (i = m * m * m + n * n * n + k * k * k) Then s = s + i End If Next MsgBox(str(s)End SubA24从三位偶数中找出其值恰好等于该数每位数字立方和的各个数之积。（结果：370）Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim i, m, n, k As Integer Dim s As integer s = 1 For i = 100 To 998 Step 2 m = i 100 n = (i Mod 100) 10 k = i Mod 10 If (i = m * m * m + n * n * n + k * k * k) Then s = s * i End If Next MsgBox(str(s)End SubA25 编写程序，用牛顿切线法求方程f(x)=2x3-8x2+15=0（其中表示幂运算），在区间(0,3)上的近似实根r，迭代初值取1，精确到0.0001。提示:牛顿切线法的计算公式为x=x-f(x)/f(x)。（结果：1.88159488）Function f(ByVal x#) As Double f = 2 * x * x * x - 8 * x * x + 15 End Function Function f1(ByVal x#) As Double f1 = 6 * x * x - 16 * x End Function Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim x1, x2, eps As Double Dim i As Integer i = 1 x1 = 1 eps = 0.0001 x2 = x1 - f(x1) / f1(x1) While (Math.Abs(x1 - x2) eps) And (i 100) i = i + 1 x1 = x2 x2 = x1 - f(x1) / f1(x1) End While If i eps) And (i 100) i = i + 1 x1 = x2 x2 = x1 - f(x1) / f1(x1) End While If i eps) And (i 100) i = i + 1 x1 = x2 x2 = f(x1) End While If i eps) And (i 100)i = i + 1 x1 = x2 x2 = x1 - f(x1) / f1(x1) End While If i 100 Then MsgBox(函数根为： + Str(x2) Else MsgBox(已迭代了100次，没有达到精度要求！) End If End SubA30 编写程序，用牛顿切线法求方程f(x)=x3+4x2-10=0（其中表示幂运算），在区间(0，5)上的近似实根r，迭代初值1，精确到0.0001。提示:牛顿切线法的计算公式为x=x-f(x)/f(x)。 （1.36523）Function f(ByVal x As Double) As Double f = x 3