C#数组和链表实现队列

  //基于数组的队列实现
    public class MyArrayQueue<T>
    {
        private T[] items;
        private int size;
        private int head;
        private int tail;

        public MyArrayQueue(int capacity)
        {
            this.items = new T[capacity];
            this.size = 0;
            this.head = this.tail = 0;
        }

        /// <summary>
        /// 入队
        /// </summary>
        /// <param name="item">入队元素</param>
        public void EnQueue(T item)
        {
            if (Size == items.Length)
                // 扩大数组容量
                ResizeCapacity(items.Length * 2);
            items[tail] = item;
            tail++;
            size++;
        }
        /// <summary>v 
        /// 出队
        /// </summary>
        /// <returns>出队元素</returns>
        public T DeQueue()
        {
            if (size == 0) return default(T);
            T item = items[head];
            items[head] = default(T);
            head++;
            if (head > 0 && Size == items.Length / 4)
                ResizeCapacity(items.Length / 2);

            size--;
            return item;
        }

        /// <summary>
        /// 重置数组大小
        /// </summary>
        /// <param name="newCapacity">新的容量</param>
        public void ResizeCapacity(int newCapacity)
        {
            T[] newItems = new T[newCapacity];
            int index = 0;
            if (newCapacity > items.Length)
            {
                for (int i = 0; i < items.Length; i++)
                    newItems[index++] = items[i];
            }
            else
            {
                for (int i = 0; i < items.Length; i++)
                {
                    if (!items[i].Equals(default(T)))
                    {
                        newItems[index++] = items[i];
                    }
                }
                head = tail = 0;
            }
            items = newItems;
        }
        /// <summary>
        /// 栈是否为空
        /// </summary>
        /// <returns>true/false</returns>
        public bool IsEmpty()
        {
            return this.size == 0;
        }

        /// <summary>
        /// 栈中节点个数
        /// </summary>
        public int Size
        {
            get
            {
                return this.size;
            }
        }
    }

public class Node<T>
    {
        public T Item { get; set; }
        public Node<T> Next { get; set; }

        public Node(T item)
        {
            this.Item = item;
        }

        public Node()
        { }
    }

    /// <summary>
    /// 基于链表的队列实现
    /// </summary>
    /// <typeparam name="T">类型</typeparam>
    public class MyLinkQueue<T>
    {
        private Node<T> head;
        private Node<T> tail;
        private int size;

        public MyLinkQueue()
        {
            this.head = null;
            this.tail = null;
            this.size = 0;
        }

        /// <summary>
        /// 入队操作
        /// </summary>
        /// <param name="node">节点元素</param>
        public void EnQueue(T item)
        {
            Node<T> oldLastNode = tail;
            tail = new Node<T>();
            tail.Item = item;

            if (IsEmpty())
            {
                head = tail;
            }
            else
            {
                oldLastNode.Next = tail;
            }

            size++;
        }

        /// <summary>
        /// 出队操作
        /// </summary>
        /// <returns>出队元素</returns>
        public T DeQueue()
        {
            T result = head.Item;
            head = head.Next;
            size--;

            if (IsEmpty())
            {
                tail = null;
            }
            return result;
        }

        /// <summary>
        /// 是否为空队列
        /// </summary>
        /// <returns>true/false</returns>
        public bool IsEmpty()
        {
            return this.size == 0;
        }

        /// <summary>
        /// 队列中节点个数
        /// </summary>
        public int Size
        {
            get
            {
                return this.size;
            }
        }
    }

 class Program
    {
        static void Main(string[] args)
        {
            // 01.基于链表的队列
            QueueWithLinkListTest();
            // 02.基于数组的队列
            //QueueWithArrayTest();
        }
        #region Method01.基于链表的队列的测试
        /// <summary>
        /// 基于链表的队列的测试
        /// </summary>
        static void QueueWithLinkListTest()
        {
            MyLinkQueue<int> queue = new MyLinkQueue<int>();
            Console.WriteLine("Is Empty:{0}", queue.IsEmpty());
            Random rand = new Random();
            // 顺序插入5个元素
            for (int i = 0; i < 5; i++)
            {
                int num = rand.Next(1, 10);
                queue.EnQueue(num);
                Console.WriteLine("{0} enqueue.", num);
            }
            Console.WriteLine("Size:{0}", queue.Size);
            Console.WriteLine("-------------------------");
            // 5个元素依次出队
            for (int i = 0; i < 5; i++)
            {
                Console.WriteLine("{0} dequeue.", queue.DeQueue());
            }
            Console.WriteLine("Size:{0}", queue.Size);
            Console.WriteLine("-------------------------");
            // 顺序插入10个元素
            for (int i = 0; i < 10; i++)
            {
                int num = rand.Next(1, 10);
                queue.EnQueue(num);
                Console.WriteLine("{0} enqueue.", num);
            }
            Console.WriteLine("Size:{0}", queue.Size);
            Console.WriteLine("-------------------------");
            // 10个元素依次出队
            for (int i = 0; i < 10; i++)
            {
                Console.WriteLine("{0} dequeue.", queue.DeQueue());
            }
            Console.WriteLine("Size:{0}", queue.Size);
        }
        #endregion

        #region Method02.基于数组的队列的测试
        /// <summary>
        /// 基于数组的队列的测试
        /// </summary>
        static void QueueWithArrayTest()
        {
            MyArrayQueue<int> queue = new MyArrayQueue<int>(5);
            Console.WriteLine("Is Empty:{0}", queue.IsEmpty());
            Console.WriteLine("Size:{0}", queue.Size);

            Random rand = new Random();
            // Test1.1:顺序插入5个数据元素
            for (int i = 0; i < 5; i++)
            {
                int num = rand.Next(1, 10);
                queue.EnQueue(num);
                Console.WriteLine("{0} enqueue.", num);
            }
            Console.WriteLine("Is Empty:{0}", queue.IsEmpty());
            Console.WriteLine("Size:{0}", queue.Size);
            // Test1.2:临时插入1个数据元素验证数组是否扩容
            queue.EnQueue(rand.Next(1, 20));
            Console.WriteLine("Size:{0}", queue.Size);
            Console.WriteLine("-------------------------");
            // Test2.1:前5个元素出队
            for (int i = 0; i < 5; i++)
            {
                Console.WriteLine("{0} dequeue.", queue.DeQueue());
            }
            Console.WriteLine("Is Empty:{0}", queue.IsEmpty());
            Console.WriteLine("Size:{0}", queue.Size);
            Console.WriteLine("-------------------------");
            // Test2.2:最后一个数据元素出队验证数组是否收缩容量
            queue.DeQueue();
            Console.WriteLine("Size:{0}", queue.Size);
            Console.WriteLine("-------------------------");
            queue.DeQueue();
        }
        #endregion
    }