C#数据结构之队列(Quene)实例详解

为了方便，定义了很多构造函数的重载版本，当然这些只是浮云，重点是理解结构：data用来保存数据，next指出下一个节点是谁
链式队列的完整实现LinkQueue.cs

using System;
using System.Text;
namespace 栈与队列
{
  public class LinkQueue:IQueue
  {
    private Node front;//队列头
    private Node rear;//队列尾
    private int num;//队列元素个数
    /// 
    /// 构造器
    /// 
    public LinkQueue() 
    {
      //初始时front,rear置为null，num置0
      front = rear = null;
      num = 0;
    }
    public int Count() 
    {
      return this.num;
    }
    public void Clear() 
    {
      front = rear = null;
      num = 0;
    }
    public bool IsEmpty() 
    {
      return (front == rear && num == 0);
    }
    //入队
    public void Enqueue(T item) 
    {
      Node q = new Node(item);
      if (rear == null)//第一个元素入列时
      {
        front = rear = q;
      }
      else
      {
        //把新元素挂到链尾
        rear.Next = q;
        //修正rear指向为最后一个元素
        rear = q;
      }
      //元素总数+1
      num++;
    }
    //出队
    public T Dequeue() 
    {
      if (IsEmpty()) 
      {
        Console.WriteLine("Queue is empty!");
        return default(T);
      }
      //取链首元素
      Node p = front;
      //链头指向后移一位
      front = front.Next;
      //如果此时链表为空，则同步修正rear
      if (front == null) 
      {
        rear = null;
      }
      num--;//个数-1
      return p.Data;
    }
    public T Peek() 
    {
      if (IsEmpty()) 
      {
        Console.WriteLine("Queue is empty!");
        return default(T);
      }
      return front.Data;
    }
    public override string ToString()
    {
      if (IsEmpty()) {
        Console.WriteLine("Queue is empty!");
      }
      StringBuilder sb = new StringBuilder();
      Node node = front;
      sb.Append(node.Data.ToString());
      while (node.Next!=null)
      {
        sb.Append("," + node.Next.Data.ToString());
        node = node.Next;
      }
      return sb.ToString().Trim(',');
    }
  }
}