//队列
        private void button12_Click(object sender, EventArgs e)
        {
            //声明队列 队列，先进先出   List就是个链表，不是先进先出。
            Queue q = new Queue();
            //添加到队列
            q.Enqueue('A');
            q.Enqueue('B');
            q.Enqueue('C');
            q.Enqueue('D');
            q.Enqueue('E');

            Console.WriteLine("cureent queue:");
            foreach (char c in q) {
                Console.Write(c + " ");
            }
            Console.WriteLine();
            q.Enqueue('V');//向 Queue 的末尾添加一个对象。
            q.Enqueue('H');
            Console.WriteLine("Current queue: ");
            foreach (char c in q)
                Console.Write(c + " ");
            Console.WriteLine();
            Console.WriteLine("Removing some values ");
            char ch = (char)q.Dequeue();//移除并返回在 Queue 的开头的对象。
            Console.WriteLine("The removed value: {0}", ch);
            ch = (char)q.Dequeue();
            Console.WriteLine("The removed value: {0}", ch);

            Console.WriteLine("获取队列的个数: {0}", q.Count);
            Console.WriteLine("判断一个元素是否在队列中", q.Contains("A"));
            //清空整个队列 q.Clear()
        }