dim i as integer

i=i+1
case else
i=1
就是在次数超过4把他还原就行

Private Sub Form_Click()
  Static i As Integer
  i = i + 1
  Select Case i
    Case 1
      Form1.Caption = &q日夏养花网uot;北京市"
    Case 2
      Form1.Caption = "上海市"
    Case 3
      Form1.Caption = "天津市"
    Case 4
      Form1.Caption = "河北省"
      i = 0
  End Select
End Sub

运行结果是：
DBC 'test(1)的输出（递归调用）
DBC 'test(2)的输出（递归调用）
DBC 'test(3)的输出
3 'test(3)的返回值

你的错误,关键在于Sum,你这里不能用整型数据来表示,很明显,应该用单精度或双精度,应该这样

Dim X As Integer, Sum As Double
For X = 1 To 100
Sum = Sum - (-1) ^ X / X
Next
Print Sum

“Dim x,y sum As Integer ”，这种声明格式是错误的，你应该写成
Dim x As Integer,y As Integer,sum As Integer
否则，VB程序运行中，只会把sum看成是Integer类型，x与y则不是Integer类型，是程序默认的数据类型--Object类型，这样会导致最后运行结果错误
这是一点，其次，你应该把sum声明为：single类型

把-1放到循环里进行判断不就得了？
把变量换为常量试试看。
3分就不错了，这题目给我做最多一分（前提是你们老师判分！）

Dim i(1 To 7) As Integer
Private Sub A()

Do While i(1) <> 8
DoEvents
If i(1) <> i(2) And i(2) <> i(3) And i(3) <> i(4) And i(4) <> i(5) And i(5) <> i(6) And i(6) <> i(7) Then showit
i(7) = i(7) + 1
If i(7) = 8 Then
i(7) = 1
i(6) = i(6) + 1
End If

If i(6) = 8 Then
i(6) = 1
i(5) = i(5) + 1
End If

If i(5) = 8 Then
i(5) = 1
i(4) = i(4) + 1
End If

If i(4) = 8 Then
i(4) = 1
i(3) = i(3) + 1
End If

If i(3) = 8 Then
i(2) = 1
i(2) = i(2) + 1
End If

If i(2) = 8 Then
i(2) = 1
i(1) = i(1) + 1
End If

Loop
End Sub

Private Function showit() As Integer
Text1.Text = Text1.Text & vbCrLf & "新的结果:"
Text1.Text = Text1.Text & vbCrLf
Dim i1 As Integer
Dim i2 As Integer
Dim strName As String
For i1 = 1 To 7
If i1 = 1 Then strName = "赵"
If i1 = 2 Then strName = "钱"
If i1 = 3 Then strName = "孙"
If i1 = 4 Then strName = "李"
If i1 = 5 Then strName = "周"
If i1 = 6 Then swww.rixia.cctrName = "吴"
If i1 = 7 Then strName = "陈"

If i(i1) = 1 Then strName = strName & "星期一"
If i(i1) = 2 Then strName = strName & "日夏养花网星期二"
If i(i1) = 3 Then strName = strName & "星期三"
If i(i1) = 4 Then strName = strName & "星期四"
If i(i1) = 5 Then strName = strName & "星期五"
If i(i1) = 6 Then strName = strName & "星期六"
If i(i1) = 7 Then strName = strName & "星期天"
Text1.Text = Text1.Text & strName & vbCrLf
Next i1
End Function
End Function

楼主的代码运行效率不错，但是还可以再简洁一些：
Dim x As Integer, sum As Double
For x = 1 To 100 Step 2
sum = sum + 1 / x - 1 / (x + 1)
Next

还需注意，sum变量的类型不能用Integer型，至于是用Single还是Double型，则看程序所需的精度和运行效率之间的平衡了。比如：
Single型的1/3等于0.3333333； pXNwzxPfr （效率较高）
Double型的1/3等于0.333333333333333；（效率较低）

楼上【0871love 】的“Sum = Sum - (-1) ^ X / X ”也很简洁，只是运行效率比较低，因为电脑运算x次方的动作是很复杂的。

我支持那位"探花"的观点,给他全分吧

Private Sub Command1_Click()
Dim a(3, 3) As Integer, i%, j%, SumA%, SumB%, t%, LSum(3) As Integer, CSum(3) As Integer
a(0, 0) = 25
a(0, 1) = 36
a(0, 2) = 78
a(0, 3) = 13
a(1, 0) = 12
a(1, 1) = 26
a(1, 2) = 88
a(1, 3) = 93
a(2, 0) = 75
a(2, 1) = 18
a(2, 2) = 22
a(2, 3) = 32
a(3, 0) = 56
a(3, 1) = 44
a(3, 2) = 36
a(3, 3) = 58
SumA = 0
SumB = 0
Print "原数组为："
For i = 0 To 3
For j = 0 To 3
Print a(i, j),
Next j
Print
Next i
For i = 0 To 3
SumA = SumA + a(i, i)
SumB = SumB + a(i, 3 - i)
Next i
Print "主对角线和为：", SumA
Print "副对角线和为：", SumB
For i = 0 To 3
For j = 0 To 3
LSum(i) = LSum(i) + a(i, j)
CSum(i) = CSum(i) + a(j, i)
Next j
Next i
For i = 0 To 3
Print "第" & i + 1 & "行的和为：", LSum(i)
Next i
For i = 0 To 3
Print "第" & i + 1 & "列的和为：", CSum(i)
Next i
For i =http://www.rixia.cc 0 To 3
t = a(0, i)
a(0, i) = a(2, i)
a(2, i) = t
t = a(1, i)
a(1, i) = a(3, i)
a(3, i) = t
Next i
Print "调换后的数组为："
For i = 0 To 3
For j = 0 To 3
Print a(i, j),
Next j
Print
Next i

End Sub

dim
a
as
long
dim
i
as
integer
a=1’设a的初始值
for
i=1
to
8‘建立一个for循环
a=a*i’执行每次循环都在a乘上该数，如第一次循环的时候a=1*1=1,第二次a=1*2=2，第三次a=2*3=6,就这样依次乘下去，便实现了连乘的效果，也就是你所要求的阶乘
next
i
text1.text=str(a)
明白了么，把乘号换成加号还可以实现连加，也就是叠加，感兴趣可以试一下