Get min and max using VBA

[mien]

hi..i tyr to get min and max value from array text.but it seem not working, the code should compare the from first line to end of file..can someone help me with the code.thanks.

 

Private Sub getminval_Click()
'Get Minimum and maximum Value
Dim strFileName, strTextLine As String
Dim arrText As Variant
Dim min, max As Double
Dim strName As String
Dim i, myFile As Integer
Dim x(100000), y(100000), z(100000) As Double
   strFileName = mstrinpfile
   myFile = FreeFile
   If strFileName = "" Then
   MsgBox "No Data ", vbOKOnly, "File Error"
   GoTo 10
   End If
   
i = 1
  
   Open strFileName For Input As #myFile
   
   Do While Not EOF(myFile)
   Input #myFile, x(i), y(i), z(i)
      
       min = z(0)
       max = z(0)
      
       If i > 1 Then
                         
       If z(i) < z(i - 1) Then
           min = z(i)
           minval.Text = min
       End If
       
       If z(i) > z(i - 1) Then
           max = z(i)
           maxval.Text = max
       End If
      
   End If
i = i + 1
Loop
10
End Sub