vb.net 斐波那契数列 求大神帮助！！！

代码：

Imports System.IO
Public Class feibo
    Function fancibo(ByVal n As Integer) As Long
        If n <= 2 Then
            Return 1
        Else
            Return fancibo(n - 1) + fancibo(n - 2)
        End If
    End Function
    Sub CreateData(ByVal max As Integer)
        Dim fs As New FileStream("fb.txt", FileMode.Create, FileAccess.Write)
        Dim mywriter As New BinaryWriter(fs)
        Dim i As Integer
        For i = 1 To max
            mywriter.Write(fancibo(i))
        Next i
        mywriter.Close()
    End Sub
    Sub ReadandDealData()
        Dim fs As New FileStream("fb.txt", FileMode.Open, FileAccess.Read)
        Dim myreader As New BinaryReader(fs)
        Dim i, s As Integer
        Dim tot As Long
        Dim avg As Single
        i = 0 : s = 0 : tot = 0 : avg = 0.0
        ListBox1.Items.Clear()
        While fs.Position < fs.Length
            s = myreader.ReadInt64()
            ListBox1.Items.Add(s)
            tot += s
            i += 1
        End While
        avg = tot / i
        ListBox1.Items.Add("数据的总和：" & tot)
        ListBox1.Items.Add("数据的平均值：" & avg)
        myreader.Close()
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        CreateData(15)
    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        ReadandDealData()
    End Sub
End Class