数据结构 -- 链式栈

栈：先进后出的数据结构。

C#版本：

namespace LinkStack
{
    /// <summary>栈</summary>
    interface IStack<T>
    {
        /// <summary>推入元素操作</summary>
        bool Push(T _data);
        /// <summary>弹出元素操作</summary>
        bool Pop(ref T _data);
        /// <summary>取栈顶元素</summary>
        bool GetTop(ref T _data);
        /// <summary>获取队列长度</summary>
        int StackLenght();
        /// <summary>是否为空</summary>
        bool IsEmpty();
        /// <summary>清空队列</summary>
        void Clear();
        /// <summary>是否满</summary>
        bool IsFull();
    }

    /// <summary>栈节点类</summary>
    class StackNode<T>
    {
        #region 私有属性
        private T data; //数据项
        private StackNode<T> next; //指针项
        #endregion
        #region 公有属性
        public T Data
        {
            get
            {
                return data;
            }
            set
            {
                data = value;
            }
        }
        public StackNode<T> Next
        {
            get
            {
                return next;
            }
            set
            {
                next = value;
            }
        }
        #endregion

        #region 构造函数
        public StackNode()
        {
            Data = default(T);
            Next = null;
        }
        public StackNode(T _data = default(T), StackNode<T> _next = null)
        {
            Data = _data;
            Next = _next;
        }
        #endregion
    }

    /// <summary>链式栈类</summary>
    class LinkStack<T>: IStack<T>
    {
        #region 成员变量
        private StackNode<T> top; //栈顶指示器
        private int nodeNum;
        #endregion

        #region 访问函数
        public LinkStack()
        {
            top = null;
            nodeNum = 0;
        }

        /// <summary>在栈顶推入一个新的元素</summary>
        public bool Push(T _data)
        {
            if (IsFull())
                return false;
            StackNode<T> q = new StackNode<T>(_data);
            if (top == null)
            {
                top = q;
            }
            else
            {
                q.Next = top;
                top = q;
            }
            ++nodeNum;
            return true;
        }

        /// <summary>弹出栈顶元素值！值保存在_data中</summary>
        public bool Pop(ref T _data)
        {
            if (IsEmpty())
                return false;

            _data = top.Data;
            top = top.Next;
            --nodeNum;

            return true;
        }

        /// <summary>取栈顶元素值！值保存在_data中</summary>
        public bool GetTop(ref T _data)
        {
            if (IsEmpty())
                return false;
            _data = top.Data;

            return true;
        }

        /// <summary>清空栈</summary>
        public void Clear()
        {
            top = null;
            nodeNum = 0;
        }

        /// <summary>栈是否为空</summary>
        public bool IsEmpty()
        {
            if (top == null && nodeNum == 0)
                return true;
            return false;
        }

        /// <summary>求栈元素个数操作</summary>
        public int StackLenght()
        {
            return nodeNum;
        }

        /// <summary>链式栈不会满的</summary>
        public bool IsFull()
        {
            return false;
        }

        #endregion

    }

}