本文實例講述了C#數據結構之堆棧(Stack)。分享給大家供大家參考，具體如下：
堆棧(Stack)最明顯的特征就是“先進后出”，本質上講堆棧也是一種線性結構，符合線性結構的基本特點：即每個節點有且只有一個前驅節點和一個后續節點。
相對前面學習過的順序表、鏈表不同的地方在于：Stack把所有操作限制在"只能在線性結構的某一端"進行，而不能在中間插入或刪除元素。下面是示意圖：
從示意圖中可以看出，堆棧有二種實現方式：基于數組的順序堆棧實現、類似鏈表的鏈式堆棧實現
先抽象堆棧的接口IStack:
namespace 棧與隊列{ public interface IStack<T> { /// <summary> /// 返回堆棧的實際元素個數 /// </summary> /// <returns></returns> int Count(); /// <summary> /// 判斷堆棧是否為空 /// </summary> /// <returns></returns> bool IsEmpty(); /// <summary> /// 清空堆棧里的元素 /// </summary> void Clear(); /// <summary> /// 入棧：將元素壓入堆棧中 /// </summary> /// <param name="item"></param> void Push(T item); /// <summary> /// 出棧：從堆棧頂取一個元素，并從堆棧中刪除 /// </summary> /// <returns></returns> T Pop(); /// <summary> /// 取堆棧頂部的元素(但不刪除) /// </summary> /// <returns></returns> T Peek(); }}順序堆棧(SeqStack)的實現：
using System;using System.Text;namespace 棧與隊列{ public class SeqStack<T>:IStack<T> { private int maxsize; private T[] data; private int top; public SeqStack(int size) { data = new T[size]; maxsize = size; top = -1; } #region //接口實現部分 public int Count() { return top + 1; } public void Clear() { top = -1; } public bool IsEmpty() { return top == -1; } public void Push(T item) { if (IsFull()) { Console.WriteLine("Stack is full"); return; } data[++top] = item; } public T Pop() { T tmp = default(T); if (IsEmpty()) { Console.WriteLine("Stack is empty"); return tmp; } tmp = data[top]; top--; return tmp; } public T Peek() { if (IsEmpty()) { Console.WriteLine("Stack is empty!"); return default(T); } return data[top]; } #endregion public bool IsFull() { return top == maxsize - 1; } public override string ToString() { StringBuilder sb = new StringBuilder(); for (int i = top;i>=0;i--) { sb.Append(data[i] + ","); } return sb.ToString().Trim(','); } }}鏈式堆棧(LinkStack)的實現
先定義節點Node.cs
namespace 棧與隊列{ public class Node<T> { private T data; private Node<T> next; public Node(T data, Node<T> next) { this.data = data; this.next = next; } public Node(Node<T> next) { this.next = next; this.data = default(T); } public Node(T data) { this.data = data; this.next = null; } public Node() { this.data = default(T); this.next = null; } public T Data { get { return this.data; } set { this.data = value; } } public Node<T> Next { get { return next; } set { next = value; } } }}下面是LinkStack.cs
using System;using System.Text;namespace 棧與隊列{ public class LinkStack<T>:IStack<T> { private Node<T> top; private int num;//節點個數 /// <summary> /// 頂部節點 /// </summary> public Node<T> Top { get { return top; } set { top = value; } } public LinkStack() { top = null; num = 0; } public int Count() { return num; } public void Clear() { top = null; num = 0; } public bool IsEmpty() { if (top == null && num == 0) { return true; } else { return false; } } public void Push(T item) { Node<T> q = new Node<T>(item); if (top == null) { top = q; } else { q.Next = top; top = q; } num++; } public T Pop() { if (IsEmpty()) { Console.WriteLine("Stack is empty!"); return default(T); } Node<T> p = top; top = top.Next; num--; return p.Data; } public T Peek() { if (IsEmpty()) { Console.WriteLine("Stack is empty!"); return default(T); } return top.Data; } public override string ToString() { StringBuilder sb = new StringBuilder(); if (top != null) { sb.Append(top.Data.ToString() + ","); Node<T> p = top; while (p.Next != null) { sb.Append(p.Next.Data.ToString()+ ","); p = p.Next; } } return sb.ToString(); } }}測試代碼片段：
Console.WriteLine("順序堆棧測試開始...");SeqStack<int> seqStack = new SeqStack<int>(10);seqStack.Push(1);seqStack.Push(2);seqStack.Push(3);Console.WriteLine(seqStack);Console.WriteLine(seqStack.Peek());Console.WriteLine(seqStack);Console.WriteLine(seqStack.Pop());Console.WriteLine(seqStack);Console.WriteLine("鏈堆棧測試開始...");LinkStack<int> linkStack = new LinkStack<int>();linkStack.Push(1);linkStack.Push(2);linkStack.Push(3);Console.WriteLine(linkStack);Console.WriteLine(linkStack.Peek());Console.WriteLine(linkStack);Console.WriteLine(linkStack.Pop());Console.WriteLine(linkStack);Console.ReadLine();注： .Net中System.Collections.Generic.Stack<T>已經提供了堆棧的基本實現，明白原理后，仍然推薦大家使用內置的實現。
希望本文所述對大家C#程序設計有所幫助。
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