程序代码如下：

Private Sub Command1_Click()

  Dim n As Integer, i As Integer

  List1.Clear

  n = Val(Text1.Text)

  If n Mod 2 = 0 Then

    For i = 2 To Int(n / 2)

      If isodd(i) = (isodd(n - i)) Then

        List1.AddItem Str(n) + " =" + Str(i) + " +" + Str(n - i)

      End If

    Next i

  Else

    Text1.Text = Str(n) + "不是偶数！"

  End If

End Sub

Private Function isodd(n As Integer) as boolean

   Dim f As integer

   f = 0

   For i = 2 To Sqr(n)

     If n Mod i = 0 Then f = 1: Exit For

   Next i

   isodd =  f

End Function

s=″I like IT very much″

flag=False:m=0

For i=1 To Len(s)

ch=Mid(s,i,1)

If ch>=″a″ And ch<=″z″ Then

If Not flag Then

   m=m+1

   flag=True

End If

Else

flag=False

End If

Next i

Text1.Text=Str(m)

s = "defghiabc"

key = Text1.Text

i = 1: j = Len(s)

Do While i <= j

    m = (i + j) \ 2

    c = Mid(s, m, 1)

    If c = key Then Exit Do

    If Mid(s, i, 1) < c Then

       If key >= Mid(s, i, 1) And key < c Then j = m - 1 Else i = m + 1

    Else

       If key > c And key <= Mid(s, j, 1) Then i = m + 1 Else j = m - 1

    End If

    ans = ans + Str(m)

Loop

运行程序后，若在文本框Text1中输入字符"b"，则变量ans的值是（  ）