Private Sub Command1_Click()

    List1.clear

    Dim a As Integer

    For i = 1 To 1000

        s = 0

        i= Len(Str(i)) - 1

        For j = 0 To i - 1

            a =           

            s = s + a ^ 3

        Next j

        If i = s Then

            List1.AddItem i

        End If

    Next i

End Sub

横线处应填写 （   ）

问题：实现上述功能的VB 代码如下，但加框处代码有错，请改正。

Private Sub Command1_Click()

    Dim n as long , sum as long , i As Long Dim x as long , y as long

    List1.Clear

    n = Val(Text1.Text) sum = 0

    For i = 10 To n

        x =               ‘①

        y = 0

        Do While x > 0

            y =         ‘②

            x = x \ 10

        Loop

        If y = i Then

            List1.additem Str(i)

            sum = sum+1

        End if

    Next i

Label1.caption = “共有”& Str(sum) & “个回文数” End Sub

①{#blank#}1{#/blank#}②{#blank#}2{#/blank#}

Dim a(1 To 1000) As Integer

Dim n As Integer

Private Sub Form_Load()

'确定n的值和数组a的各个元素值，即每根棍子的长度值，代码略

End Sub

Function max (x As Integer, y As Integer) As Integer

    If x>y Then

        max=x

    Else

        max=y

    End If

End Function

Private Sub Command1_Click()

    Dim i As Integer, J As Integer, K As Integer

    Dim ans As Integer, c As Integer, longest As Integer,

    rest As Integer

    ans=0

    '让i<j<k，保证棍子不会被重复选中

    For i=1 To n

        For j=i+1 To n

            For k=j+1 To n

                c=a(i)+a(j)+a(k)

                longest=      '①

                rest=c-longest        'rest 保存最短的两条边的和

                If Then      '②

                    ans=max(ans, c)

                End If

            Next k

        Next j

    Next i

    Print ans

End Sub