2017年山西高考排名:程序错在哪里?(VB.NET的题目)

在文本框内输入:四川\北京\上海\重庆\南京
按字典顺序排列,程序运行结果总是不对,请大家看一下,错在哪里?

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim s() As String
s = Split(TextBox1.Text, "\")
Dim c As String
For Each c In s
Response.Write(c & "<br>")
Next

Dim sp As String, n As Int16
sort(s)
For n = 0 To s.Length - 1
sp = sp & s(n) & " "
Next
sp = Trim(sp)
Response.Write("<br>" & sp)
End Sub

Sub sort(ByVal a() As String)
Dim i, j As Int32
Dim t As String
For i = 1 To a.Length
For j = i + 1 To a.Length
If a(j - 1) > a(j) Then
t = a(j - 1)
a(j - 1) = a(j)
a(j) = t
End If
Next
Next
For i = 1 To a.Length
Response.Write("<br>" & a(i))
Next
End Sub
End Class