m=1：k=1

    For i=2 To 10

      If a(i)<a(i-1)Then

    k=k+1

         If k>m Then m=k

       Else

         k=1

       End If

    Next i

    Text1．Text=Str(m)

  End Sub

执行该程序段，文本框Text1中显示的是 （  ）

x=″abcdcba″:ans=0

For i=1 To Len(x)\2

If Mid(x,i,1)=Mid(x,Len(x)-i+1,1) Then

ans=ans+1

end if

Next i

Text1.Text=Str(ans)

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 s1 As String

Dim s2 As String

Dim s3 As String

Dim l1 As Integer

Dim l2 As Integer

Dim l3 As Integer

Dim a(1 To 100) As Integer

Dim b(1 To 100) As Integer

Dim c(1 To 100) As Integer

Dim t As Integer

s1 = Text1.Text

s2 = Text2.Text

l1 = Len(s1)

l2 = Len(s2)

For i = l1 To 1 Step -1

 a(i) ={#blank#}1{#/blank#}

Next

For i = l2 To 1 Step -1

 b(i) =Val(Mid(s2, l2 - i + 1, 1))

Next

If l1 > l2 Then l3 = l1 Else l3 = l2

t = 0

For i = 1 To l3

  c(i) = a(i) + b(i) + t

  t = c(i) \ 10

  c(i) ={#blank#}2{#/blank#}

Next

For i = 1 To l3

  s3 = Str(c(i)) + s3

Next

If{#blank#}3{#/blank#}Then s3 = “1” + s3

Text3.Text = s3

End Sub

If a>b Then t=a:a=b:b=t s=a+b

a=s-a b=s-b

已知变量a和b中的值均为正整数，且a的值大于b的值，执行该程序段后，值最终未发生改变的变量是（  ）