边看边写（用两个栈实现队列功能）

#region 用两个栈实现队列的功能
    class CQueue<T> where T : IComparable<T>
    {
        private Stack<T> enterQ = new Stack<T>();
        private Stack<T> outQ = new Stack<T>();


        public void AppendTail(T  data)
        {
            enterQ.Push(data);
        }
        public T DeleteTail()
        {
            T outData;
            if (outQ.Count()== 0)
            {
                while (enterQ.Count() > 0)
                {
                    outQ.Push(enterQ.Pop());
                }


            }
            if (outQ.Count == 0)
                outData = default(T);
            else
                outData = outQ.Pop();
            return outData;
        }
    }
    #endregion