C# 数据结构-队列（自练习）

列的操作原则是先进先出的，所以队列又称作FIFO表(First In First Out)  

队列的基本运算也有六种： 

置空队 ：InitQueue(Q) 

判队空： QueueEmpty(Q) 

判队满： QueueFull(Q) 

入队 ： EnQueue(Q,x) 

出队 ： DeQueue(Q) 

取队头元素： QueueFront(Q),不同与出队，队头元素仍然保留 

 

namespace Queue

{

    /// <summary>

    /// Implement Queue in Array.

    /// </summary>

    class Queue

    {

        private int[] items;

        private int count;

 

        /// <summary>

        /// Initial Queue.

        /// </summary>

        /// <param name="capability"></param>

        public Queue(int capability)

        {

            //capability should always bigger than 0.

            if (capability > 0)

                items = new int[capability];

            else

                throw new IndexOutOfRangeException("Array should be more than 0.");

            this.count = 0;

        }

        /// <summary>

        /// Add Item at the end of Queue.

        /// </summary>

        /// <param name="item"></param>

        public void EnQueue(int item)

        {

            MoveAllNext();

            items[0] = item;

            this.count++;

        }       

        /// <summary>

        /// Delete item at the front of Queue.

        /// Return the deleted item of Queue.

        /// </summary>

        /// <returns></returns>

        public int DeQueue()

        {

            int temp = items[count - 1];

            items[count - 1] = 0;

            count--;

            return temp;           

        }

        /// <summary>

        /// Return the front item of Queue without deleting.

        /// </summary>

        /// <returns></returns>

        public int Peek()

        {

            if (count > 0 && count <= items.Length)

                return items[count - 1];

            else

                throw new IndexOutOfRangeException("Count is out of Array Range.");

        }

        /// <summary>

        /// If Queue is Full, return true.

        /// </summary>

        /// <returns></returns>

        public bool IsFull()

        {

            return this.count == items.Length ? true : false;

        }

        /// <summary>

        /// If Queue is Empty, return true.

        /// </summary>

        /// <returns></returns>

        public bool IsEmpty()

        {

            return this.count == 0 ? true : false; ;

        }

        /// <summary>

        /// Move All Items in Array to next sequently.

        /// the last element in Array will move out of Array.

        /// </summary>

        private void MoveAllNext()

        {

            if (count == 0)

                return;

            else if (count > 0 && count <= items.Length)

            {

                int[] temp = new int[items.Length];

                temp[0] = 0;

                for (int i = 1; i < count; i++)

                {

                    temp[i] = items[i - 1];

                }

                items = temp;

            }

            else

                throw new IndexOutOfRangeException("Count is out of Array Range.");

        }

        /// <summary>

        /// Move All Items in Array to front sequently.

        /// the original element in Array will be over writed.

        /// </summary>

        private void MoveAllFront()

        {

            if (count == 0)

                return;

            else if (count > 0 && count <= items.Length)

            {

                int[] temp = new int[items.Length];               

                for (int i = 1; i < count; i++)

                {

                    temp[i - 1] = items[i];

                }

                items = temp;

            }

            else

                throw new IndexOutOfRangeException("Count is out of Array Range.");

        }       

    }

}