vb点虐 大题 vbnet implements

vb点虐 面试题，请大家帮忙，谢谢。

如果需要讲详细一点,那就加我QQ531412815

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第4题,潜在的错误,这里的错误不是常规错误,属于那种只有在运行是才知道的错误:

Catch ex As Exception

MsgBox(ex.StackTrace)

'永远不会查找下面的错误

Catch ex As ArgumentNullException

MsgBox("Input Test box cannot be null.")

Catch ex As OverflowException

MsgBox("Input Test box 2 cannot be zero!")

Catch ex As FormatException

MsgBox("Input Test box should be numeric format!")

结构化错误处理永远达不到下面这里,因为Catch ex As Exception 已经处理了所有错误.

第5题：

00123

1000 60.50

2000 60.00

3500 59.50

---- -----

6500 60.00

00124

3000 60.50

---- -----

3000 60.50

00125

2000 59.50

1000 58.00

---- -----

3000 58.75

就是按照Ref_ID 分类，有一种方法就是按照Ref_ID 分组，也就是使用SQL语言，不过这里需要该很多，

我就不用了，那么就稍微复杂一点，使用FIND方法,不过有一点必须注意REF_ID必须排序，因为数据库中

已经排好序了，我就不用排了。

Dim rst as ADODB.Recordset

dim refID as string

Rst = GetRecordset

Do While Not rst.EOF

refid=rst(0)

Console.writeline(rst.Fields("Ref_ID")

do

Console.writeline rst.Fields("Qty") vbcrlf rst.Fields("Price"))

rst.MoveNext()

loop while rst(0)=refid

Loop

第6题：就是从一个集合中取元素输出的问题

比较简单的办法就是使用递归

以下是使用VB的方法(可以移植到VB.NET上,因为我对VB.NET的数组到现在还不太会,所以就将就一下)

Dim bUse() As Boolean

Dim lStr() As String * 1

Dim nCount As Byte

-----------------------------------------------------------------------------------

Public Sub Combination(lstStr As String)

Dim i As Byte

Dim j As Byte

Dim StrLen As Byte

StrLen = Len(lstStr)

ReDim bUse(1 To StrLen) As Boolean

ReDim lStr(1 To StrLen) As String * 1

For i = 1 To StrLen

lStr(i) = Mid(lstStr, i, 1)

Next

For i = 1 To StrLen

nCount = i

GoWith StrLen, 1, 0, ""

Next

End Sub

------------------------------------------------------------------------------------

Public Sub GoWith(ECount As Byte, nStart As Byte, Deep As Byte, lastStr As String)

Dim i As Byte

If Deep = nCount Then

Debug.Print lastStr

Exit Sub

End If

For i = nStart To ECount

If Not bUse(i) Then

bUse(i) = True

GoWith ECount, i, Deep + 1, lastStr lStr(i)

bUse(i) = False

End If

Next

End Sub

--------------------------------------------------------------------------------------

Private Sub Form_Load()

Combination "wxyz"

End Sub

--------------------------------------------------------------------------------------

其中GOWITH是真正的递归函数,而Combination是用来预处理字符的

全局变量:

BUSE：用来确定是否使用过这个元素

lSTR：用来保存字符元素

NCOUNT：用来限制递归函数的深度，换句话说，就是输出元素组中的元素个数

实际测试成功，另外我对前三题很感兴趣，希望能够传给我

vb点虐 的两道题

1.编程求1!+3!+5!+....+n! N由inputbox获取

Function Math(ByVal N As Integer) As Integer

Dim c As Integer = 1

For i = 1 To N

c *= i

Next

Return c

End Function

Dim N As String = InputBox("输入N的值.")

If N = "" Then Return

MessageBox.Show(Math(N))

2.用最简单的方法将个位数和十位数互换,一定要最简单的方法..比如31换成13.

Dim s As String = InputBox("输入一个十位数.")

If s = "" Then Return

MessageBox.Show(StrReverse(s))

VB.NET的题目哈 随机产生20个大写字母，求出现次数最多的字母及出现次数，还有求出现次数为0的字母有哪些

Imports System.Text.RegularExpressions

Public Class Form1

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

Dim a As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

Dim g() As Char = a.ToCharArray

Dim MyRandom As New Random

Dim bs As String = ""

For i = 1 To 20

bs = g(MyRandom.Next(0, g.GetUpperBound(0) + 1))

Next

Dim gs() As String = (From mt As Match In Regex.Matches(bs, "[A-Z]") Select mt.Value).ToArray

System.Array.Sort(gs)

gs = (From mt As Match In Regex.Matches(Join(gs, ""), "([A-Z])\1*") Select mt.Value).ToArray

Dim g_len() As Integer

g_len = (From mt As Match In Regex.Matches(Join(gs, ""), "([A-Z])\1*") Select mt.Length).ToArray ' 使用数组元素作为计数器g_len

System.Array.Sort(g_len, gs)

Label1.Text = "出现次数最多的字母：" gs(gs.GetUpperBound(0)).Substring(0, 1) " 共出现" g_len(g_len.GetUpperBound(0)) "次" vbCrLf "没有出现的字母是：" Join(a.Split(bs.ToCharArray), "")

End Sub

End Class