学步园

队列的概念和定义

基本操作：

• 入队：将一个数据插入到队尾的操作。
• 出队：读取队头结点数据并删除该结点的操作

顺序队列的两个指示器与队列中数据元素的关系图

循环顺序队列

循环顺序队列操作

队列的实现

using System;
namespace EveryDayStudy.数据结构
{
    public class DAPQueue
    {
        private object[] _array; //存放元素的数组
        private int _growFactor; //增长因子
        private int _head;//队头指针
        private const int _MinimumGrow = 4;//最小增长值
        private const int _ShrinkThreshold = 0x20;//初始容量
        private int _size;//指示元素个数
        private int _tail;//队尾指针

        public DAPQueue() : this(_ShrinkThreshold, 2f)
        {
        }

        public DAPQueue(int capacity,float growFactor)
        {
            if (capacitythrow new ArgumentOutOfRangeException("capacity","初始容量不能小于0");
            }
            if (growFactor10.0)
            {
                throw  new ArgumentOutOfRangeException("growFactor","增长因子必须在1.0到是10.0之间");
            }

            _array = new object[capacity];
            _head = 0;
            _tail = 0;
            _size = 0;
            _growFactor = (int) (growFactor*100f);
        }

        /// 

        /// 出队
        /// 
        /// 
        public virtual object Dequeue()
        {
            if (_size ==0)
            {
                throw  new InvalidOperationException("队列为空。"); //队下溢
            }
            object obj2 = _array[_head];
            _array[_head] = null;//删除出队指针
            _head = (_head + 1)%_array.Length; //移动队头指针
            _size--;
            return obj2;
        }

        /// 

        /// 入队
        /// 
        /// 
        public virtual void Enqueue(object obj)
        {
            if (_size == _array.Length)
            {
                int capacity = (int)((_array.Length*_growFactor)/100L);
                if (capacity /// 
/// 内存搬家
        /// 
/// 
        private void SetCapacity(int capacity)
        {
            //在内存中开辟新空间
            object[] destinationArray = new object[capacity];
            if (_head<_tail class="rem">//当头指针在尾指针前面时
                Array.Copy(_array,_head,destinationArray,0,_size);
            }
                //当头指针在尾指针后面时
            else
            {
                //先搬头指针后面的元素再搬数组头部到尾指针之间的元素
                Array.Copy(_array, _head, destinationArray, 0, _array.Length - _head);
                Array.Copy(_array, 0, destinationArray, _array.Length - _head, _tail);
            }

            _array = destinationArray;
            _head = 0;
            _tail = (_size == capacity) ? 0 : _size;
        }

        /// 

        /// 元素个数
        /// 
        public  virtual  int Count
        {
            get
            {
                return _size;
            }
        }
    }
}