2010春江苏省VB05上机答案

2010年（春）上机 Visual Basic（VB05）答案
一、改错
【题目】本程序的功能是，随机生成n个两位整数（n利用键盘输入），存入一个数组。

再依次找出数组中的最大元素并将其删除，删除的方法是将最大元素后面的元素依次前移一个位置，数组长度减1。

重复上述过程，直到得到只有一个元素的数组为止。

Option Explicit
Private Sub Command1_Click()
Dim a() As Integer, n As Integer, mv As Integer, mp As Integer
Dim i As Integer, j As Integer, st As String
n = InputBox("元素个数", "数组处理", 10)
Randomize
ReDim a(n)
For i = 1 To n
a(i) = Int(Rnd * 90) + 10
Text1 = Text1 & Str(a(i))
Next i
'st = "" '位置错
For i = 1 To n - 1
Call maxv(a, mv, mp)
For j = mp To UBound(a) - 1 'err To n - 1
a(j) = a(j + 1)
Next j
ReDim Preserve a(UBound(a) - 1) 'err 无Preserve
For j = 1 To UBound(a)
st = st & Str(a(j))
Next j
List1.AddItem st
st = ""
Next i
End Sub
Private Sub maxv(a() As Integer, maxe As Integer, mp As Integer)
Dim i As Integer
maxe = a(1): mp = 1
For i = 2 To UBound(a)
If a(i) > maxe Then
maxe = a(i): mp = i
End If
Next i
End Sub
二、编程题
【题目】编写程序，找出a～b之间所有的循环素数。

所谓循环素数是指本身为素数，且其
各位数字循环位移组成的新数全部为素数的整数。

例如719是素数，而197、971也都是素数，所以719是循环素数。

Option Explicit
Option Base 1
Private Sub Command1_Click()
Dim i As Integer, j As Integer, na() As Integer
Dim a As Integer, b As Integer
a = Text1:
b = Text2
For i = a To b
Call change(i, na)
For j = 1 To UBound(na)
If Not prime(na(j)) Then Exit For
Next j
If j > UBound(na) Then
List1.AddItem i
End If
Next i
End Sub
Private Function prime(n As Integer) As Boolean
Dim i As Integer
For i = 2 To Sqr(n)
If n Mod i = 0 Then Exit Function
Next i
prime = True
End Function
Private Sub change(n As Integer, na() As Integer)
Dim p As String, i As Integer, k As Integer
p = CStr(n)
k = Len(p)
ReDim na(k)
na(1) = n
For i = 2 To UBound(na)
na(i) = V al(Mid(p, i, k - i + 1) & Left(p, i - 1))
Next i
End Sub
Private Sub Command2_Click()
Text1 = "": Text2 = ""
List1.Clear
Text1.SetFocus
End Sub
Private Sub Command3_Click()
End
End Sub。