实验31 循环结构程序设计.docx

实验31 循环结构程序设计1. 用ForNext语句编写计算1/(1*2)+1/(2*3)+1/(n*(n+1)的程序，并显示其计算结果 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim i, n As Integer, s As Double n = InputBox(输入求和级数n的值：) s = 0 For i = 1 To n s = s + 1 / (i * (i + 1) Next MsgBox(1/(1*2)+1/(2*3) & 1/ & i - 1 & *( & i - 1 & +1)= & Format(s, 0.0000000)End Sub2. 显示图形* * * * * * * * * * * * * * * *Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click Dim r, s, c, j As Integer, y(5), ys As String ys = r = 1 Do While r = 4 c = 10 - r : s = 1 y(r) = y(r) & Space(c + s) 定一行中显示的起始位置 Do While s = 1 c = 10 - r : s = 1 ys = ys & Space(c + s) Do While s = 50 Then Man_over50 = Man_over50 + 1 ElseIf grade(i) = grade(i) Then t = grade(i) : grade(i) = grade(j) : grade(j) = t End If Next j Next i s = For i = 1 To 20 s = s & grade( & i & )= & grade(i) & If i Mod 3 = 0 Then s = s & Chr(10) Next i MsgBox(s)End Sub7. 用随机函数和取整函数生成一个8位数的整数，判断09这10个数字在生成的8位数的整数中出现的次数，并显示判断结果。（1） Private Sub Button8_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button8.Click 用随机函数和取整函数生成一个8位数的整数，判断0-9这10个数在该数中出现的次数 Dim x As Long, x_string, s As String, cs(9), i, j, num As Integer Randomize() x = Int(Rnd() * 90000000 + 10000000) x_string = Trim(Str(x) trim()函数是去掉输入数值竟str()函数转换在数字前增加的符号位 For i = 0 To 9 cs(i) = 0 累加器清零 Next For i = 1 To 8 num = Mid(x_string, i, 1) Select Case num Case 0 cs(0) = cs(0) + 1 Case 1 cs(1) = cs(1) + 1 Case 2 cs(2) = cs(2) + 1 Case 3 cs(3) = cs(3) + 1 Case 4 cs(4) = cs(4) + 1 Case 5 cs(5) = cs(5) + 1 Case 6 cs(6) = cs(6) + 1 Case 7 cs(7) = cs(7) + 1 Case 8 cs(8) = cs(8) + 1 Case 9 cs(9) = cs(9) + 1 End Select Next i s = 在 & x_string & 中 & Chr(10) s = s & 0出现的次数= & cs(0) & Chr(10) s = s & 1出现的次数= & cs(1) & Chr(10) s = s & 2出现的次数= & cs(2) & Chr(10) s = s & 3出现的次数= & cs(3) & Chr(10) s = s & 4出现的次数= & cs(4) & Chr(10) s = s & 5出现的次数= & cs(5) & Chr(10) s = s & 6出现的次数= & cs(6) & Chr(10) s = s & 7出现的次数= & cs(7) & Chr(10) s = s & 8出现的次数= & cs(8) & Chr(10) s = s & 9出现的次数= & cs(9) & Chr(10) MsgBox(s) End Sub （2） Private Sub Button9_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button9.Click 用随机函数和取整函数生成一个8位数的整数，判断0-9这10个数在该数中出现的次数，结果防在数组 Dim x As Long, x_string, s As String, i, j, num As Integer Randomize() x = Int(Rnd() * 90000000 + 10000000) x_string = Trim(Str(x) trim()函数是去掉输入数值竟str()函数转换在数字前增加的符号位 Dim cs(9) As Integer cs(i)数组是作为8个累加器，用来累计0-9这10个数字在前面产生的8位数中出现的次数 For i = 0 To 9 cs(i) = 0 累加器清零 Next i For i = 1 To 8 num = Mid(x_string, i, 1) For j = 0 To 9 If Val(num) = j Then cs(j) = cs(j) + 1 与数字对应的累加器+1 Next j Next i s = For i = 0 To 9 s = s & i & 在 & x_string & 中出现的次数= & cs(i) & Chr(10) Next i MsgBox(s) End Sub8. 编写用随机函数和取整函数产生20个8位整数的程序 Private Sub Button10_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button10.Click 产生20个8位整数 Dim x(0 To 19) As Long, x_string(0 To 19), s As String s = For i = 0 To 19 Randomize() x(i) = Int(Rnd() * 900