长度小于等于 100），在列表框 List1 里输出所有配对括号在表达式中的位置。例如在文本框 Text1 里入：“12*(3-(1+2))*3”，程序运行效果如图所示。

实现上述功能的 VB 代码如下，在划线的地方填入合适代码，完善程序。Private Sub Command1_Click()

Dim s As String

Dim a(1 To 100) As Integer

i = 1 top = 0

Do While i <= Len(s)

     If Mid(s, i, 1) = "(" Then

        top = top + 1

        {#blank#}1{#/blank#} 

     End If

     If Mid(s, i, 1) = ")" Then

        List1.AddItem Str(a(top)) + "    " + Str(i)

        {#blank#}2{#/blank#} 

     End If

     i=i+1 Loop

End Sub

实现上述功能的VB程序如下，请在划线处填入合适的代码。

Private Sub Command1_Click()

Dim a(1 To 10) As Integer    ‘存储0~9每个数字出现的次数

Dim b(1 To 26) As Integer    ‘存储a~z每个字母出现的次数

Dim zf As String, x As String, p As Integer

Dim maxa As Integer, maxb As Integer

{#blank#}1{#/blank#}

For i = 1 To Len(zf)

 x = Mid(zf, i, 1)

 If pd(x) = 1 Then

  p = Asc(x) - Asc(“0”) + 1

  a(p) = a(p) + 1

  {#blank#}2{#/blank#}

  p = Asc(x) - Asc(“A”) + 1

  b(p) = b(p) + 1

 Else

  p = Asc(x) - Asc(“a”) + 1

  b(p) = b(p) + 1

 End If

Next i

k = a(1):maxa = 1

For i = 2 To 10

 If a(i) > k Then k = a(i):maxa = i

Next i

k = b(1) :maxb = 1

For i = 2 To 26

 If{#blank#}3{#/blank#}Then k = b(i) :maxb = i

Next i

Label1.Caption =“出现最多的数字是” + Chr(maxa+ Asc(“0”)-1)

Label2.Caption = “出现最多的字母是” + Chr(maxb + Asc(“A”)-1)

End Sub

Function pd(ch As String) As Integer ’函数用于判断每个字符类型

 If ch >= “0” And ch <= “9” Then pd = 2

 If ch >= “A” And ch <= “Z” Then pd = 2

 If ch >= “a” And ch <= “z” Then pd = 3

End Function

i = 1

Do While i<=6

    a(i) = Int(Rnd * 10) + 1

    If a(i) Mod 2 = i Mod 2 Then i = i + 1

Loop

For i = 1 To 2

    k = 1

    For j = 1 To 6 - i * 2

        If a(j) * k > a(j + 2) * k Then

            t = a(j): a(j) = a(j + 2): a(j + 2) = t

        End If

        k = -k

    Next j

Next i

执行该程序段后，在下列选项中，a(1)~a(6)各元素值可能的是（  ）

For i = 1 To 9 Step 2

  b(a(i) Mod 10) = b(a(i) Mod 10) + 1

Next i

s = 0

For i = 0 To 9 Step 3

  s =s + b(i)

Next i

数组b各元素初始值为0， 数组元素a(1)到a(9)的值依次为“29,74,12,38,16,45,21,57,33”,则执行该程序段后，s的值为（  ）