冒泡排序？？？4.1请问问题出在哪

 运行不出结果，全是00000000000000

Option Explicit

Dim a(9) As Long

Private Sub Command1_Click()

Dim i As Long, j As Long, b As Long

    For i = 1 To 9

        For j = 0 To 9 - i

            If a(j) > a(j + 1) Then

                b = a(j)

                a(j) = a(j + 1)

                a(j + 1) = b

            End If

        Next j

    Next i

    For i = 0 To 9

        Text1.Text = Text1.Text + CStr(a(i)) + ""

        If i = 4 Then Text1.Text = Text1.Text + Chr(13) + Chr(10)

    Next i

End Sub

Private Sub Command2_Click()

    Dim i As Long, M

    Text1.Text = ""

    For i = 0 To 9

N:

        '弹出提示对话框输入数字

        M = InputBox("请输入排序的10个数字，这是第" & CStr(i + 1) & "个", "提示", "")

        If IsNumeric(i) Then

            a(i) = M

        Else

            MsgBox "请输入数字", vbOKOnly, "错误"

            GoTo N

        End If

    Next i

End Sub