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江苏省等级考试二级VB上机试卷2005年（秋）及参考答案

【题目1】本程序的功能是：找出2~10000之间可以表示成22-1形式的素数.本题程序界面见图1.

答： 源程序： Option Explicit

Private Sub Command1_Click()

Dim Exp As Integer, Idx As Integer For Idx = 2 To 10000

If Mersenne(Idx, Exp) Then If Prime(Idx) Then

List1.AddItem Idx & \ End If End If Exp = 0 Next Idx End Sub

Private Function Mersenne(N As Integer, Exp As Integer) As Boolean Dim M As Integer, Ex As Long M = N Ex = 1

Do While M > Ex Exp = Exp + 1 Ex = Ex * 2 Loop

If M = Ex - 1 Then Mersenne = True End If End Function

Private Function Prime(N As Integer) As Boolean Dim K As Integer For K = 2 To Sqr(N)

If N Mod K = 0 Then Exit Function Next K Prime = True End Function

【题目2】将1～9这9个数字顺序排列围成一圈,从中任意一个数字开始,依次将其分成三段,每段数字连在一起算一个数,得到一个2位数、一个3位数和一个4位数,将这三个数相加,使其和数能被77整除.编写一个能找出这三个数的程序. 【编程要求】

1.程序参考界面如图2所示,编程时不得增加或减少界面对象或改变对象的种类,窗体及界面元素大小适中,且均可见;

2.单击“运行”按钮,找出符合条件的三个数,并将它们显示在文本框中;

3.单击“清理”按钮,则将文本框清空,并将焦点设置在“运行”按钮上;单击“结束”按钮,结束程序运行; 4.程序中必须包含一个将数字分段,得到一个2位数、一个3位数和一个4位数的通用过程.

答：源程序：

Private Sub Command1_Click()

Dim s As String, i As Integer, sum As Integer, s1 As Integer, s2 As Integer, s3 As Integer s = \

For i = 1 To Len(s)

Call part(s, i, s1, s2, s3) If (s1 + s2 + s3) Mod 77 = 0 Then

Text1.Text = Text1.Text & \& vbCrLf End If Next i End Sub

Private Sub part(ByVal s As String, i As Integer, s1, s2, s3) s = s & s

s1 = Int(Mid(s, i, 2)) s2 = Int(Mid(s, i + 2, 3)) s3 = Int(Mid(s, i + 5, 4)) End Sub

Private Sub Command2_Click() End End Sub

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