Code Explaination

private Int32 check(String u, String p)
    {
        SqlCommand cmd = new SqlCommand();
        cmd.CommandText = "logincheck";
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Connection = con;
        cmd.Parameters.Add("@u", SqlDbType.VarChar, 50).Value = u;
        cmd.Parameters.Add("@p", SqlDbType.VarChar, 50).Value = p;

        SqlParameter p1=new SqlParameter("@ret",SqlDbType .Int);
->//EXPLAIN NEED OF THIS PARTICULAR LINE 
     
        p1.Direction = ParameterDirection.ReturnValue;
        cmd.Parameters.Add (p1 );
        cmd.ExecuteNonQuery();
        Int32 k;
        k = Convert.ToInt32(cmd.Parameters["@ret"].Value);
        cmd.Dispose();
        return k;

     }