this is a sample code
Dim s1 As String = "abc"
Dim s2 As String = "abgc"
Dim diffcnt As Integer = 0
For Each c As Char In s1
If Not s2.Contains(c) Then
diffcnt = diffcnt + 1
End If
Next
For Each c As Char In s2
If Not s1.Contains(c) Then
diffcnt = diffcnt + 1
End If
Next
Response.Write(diffcnt & " letter(s) is different")
