Parameter out sample

alter proc Proc_Grade    
(     
@class Varchar(100),     
@Mark numeric(15, 2)  ,   
@ret varchar(100) out   
)     
As     
Begin   
DECLARE @OUTPUT varchar(100)
Set @ret=[dbo].Grade (@class ,@Mark)
print @ret
End


 Public Function Geetgrade(ByVal classs As String, ByVal ADDNEW As Double) As String
        Dim result As String
        con.Close()
        con.Open()
        cmd.Parameters.Clear()
        cmd = con.CreateCommand
        cmd.CommandText = "Proc_Grade"
        cmd.CommandType = CommandType.StoredProcedure
        cmd.Parameters.AddWithValue("@class", classs)
        cmd.Parameters.AddWithValue("@Mark", ADDNEW)
        cmd.Parameters.Add("@ret", SqlDbType.VarChar, 100).Direction = ParameterDirection.Output
        cmd.ExecuteNonQuery()
        result = cmd.Parameters("@ret").Value
        con.Close()
        Return result
    End Function