i = 1

Do While i <= 5

      If i = 0 or a(i - 1) <= a(i) Then

        i = i + 1

      Else

        t = a(i): a(i) = a(i - 1): a(i - 1) = t

        i = i - 1

      End If

Loop

For i = 1 To 5

      List2.AddItem  a(i)

Next i

数组元素a(0)到a(5)的值依次为“0，71，22，48，79，27”，经过该程序段“加工”后，数组元素a(4)的值为（   ）

实现上述功能的VB程序如下，但横线处代码有错，请改正。

Private Sub Command1_Click()

    Dim a As String

    Dim x As Integer, s As Integer, k As Integer

    a = Text1.Text

    x = 1: s = 0: k = 0

    For i = 1 To Len(a)

        '如果输入的不是0到9的数字或者空格，则给出错误提示后结束子程序

        If (Asc(Mid(a, i, 1)) < 48 Or Asc(Mid(a, i,1)) > 57)  or(Asc(Mid(a,i,1))= 32)  then’{#blank#}1{#/blank#}Label1.Caption = "只能输入数字或空格"

            Exit Sub

        End If

        If Mid(a, i, 1) = " " Then

            s = s + Mid(a,x,i)’{#blank#}2{#/blank#}

            x = i + 1

            k = k + 1

        End If

    Next i

    Label1.Caption = "这" + Str(k) + "个数的和为:" + Str(s)

End Sub

Private Sub Command1_Click()

  Dim sum As  Double, x As Double

  sum=0

  n=0

  For i=1 To 5

     x=n/i

     n=n+1

     sum=sum+x

  Next i

End Sub

该程序计算了一个表达式的值，这个表达式是（  ）

n = Len(Text1.Text)

For i = 1 To n

 a(i) = Mid(Text1.Text, i, 1)

Next i

Do While n > 1

 If Asc(a(n)) >= Asc(a(n - 1)) Then

    m = 1

 Else

    m = 2

 End If

 b(m) = b(m) + 1

 n = n-1

Loop

数组b各元素的初始值都为0，文本框Text1的内容为“2018Python”。执行程序后，变量b(1)的值为（  ）