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C#數(shù)據(jù)結(jié)構(gòu)之堆棧(Stack)實(shí)例詳解

更新時(shí)間：2015年11月27日 14:39:52 作者：Jimmy.Yang

這篇文章主要介紹了C#數(shù)據(jù)結(jié)構(gòu)之堆棧(Stack),結(jié)合實(shí)例形式較為詳細(xì)的分析了堆棧的原理與C#實(shí)現(xiàn)堆棧功能的相關(guān)技巧,具有一定參考借鑒價(jià)值,需要的朋友可以參考下

本文實(shí)例講述了C#數(shù)據(jù)結(jié)構(gòu)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(jìn)后出”，本質(zhì)上講堆棧也是一種線性結(jié)構(gòu)，符合線性結(jié)構(gòu)的基本特點(diǎn)：即每個(gè)節(jié)點(diǎn)有且只有一個(gè)前驅(qū)節(jié)點(diǎn)和一個(gè)后續(xù)節(jié)點(diǎn)。

相對(duì)前面學(xué)習(xí)過(guò)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(jié)構(gòu)的某一端"進(jìn)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(shí)現(xiàn)方式：基于數(shù)組的順序堆棧實(shí)現(xiàn)、類似鏈表的鏈?zhǔn)蕉褩?shí)現(xiàn)

先抽象堆棧的接口IStack:

namespace 棧與隊(duì)列
{
  public interface IStack<T>
  {
    /// <summary>
    /// 返回堆棧的實(shí)際元素個(gè)數(shù)
    /// </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(gè)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(shí)現(xiàn)：

using System;
using System.Text;
namespace 棧與隊(duì)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(shí)現(xiàn)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?zhǔn)蕉褩?LinkStack)的實(shí)現(xiàn)

先定義節(jié)點(diǎn)Node.cs

namespace 棧與隊(duì)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(duì)列
{
  public class LinkStack<T>:IStack<T>
  {
    private Node<T> top;
    private int num;//節(jié)點(diǎn)個(gè)數(shù)
    /// <summary>
    /// 頂部節(jié)點(diǎn)
    /// </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(cè)試代碼片段：

Console.WriteLine("順序堆棧測(cè)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(cè)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(jīng)提供了堆棧的基本實(shí)現(xiàn)，明白原理后，仍然推薦大家使用內(nèi)置的實(shí)現(xiàn)。

希望本文所述對(duì)大家C#程序設(shè)計(jì)有所幫助。

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