static void Main(string[] args)
        {
            /**泛型**/
            LinkedList<int> ll = new LinkedList<int>();
            for (int i = 0; i < 10; i++)
            {
                ll.Add(i);
            }

            Console.Write(ll);
            Console.WriteLine("  Done.");

            LinkedList<Employee> employees = new LinkedList<Employee>();
            employees.Add(new Employee("Jason1"));
            employees.Add(new Employee("Jason2"));
            employees.Add(new Employee("Jason3"));
            employees.Add(new Employee("Jason4"));

            Console.Write(employees);
            Console.WriteLine("  Done.");

            Console.WriteLine("The fourth integer is {0}.", ll[3]);

            Employee d = (Employee)employees[1];
            Console.WriteLine("The second Employee is {0}.", d);

            Console.ReadLine();
        }