转：C#数据结构和算法学习系列七----队列、队列的实现和应用

队列是一种把数据从表的末端放入并在表的前端移除的数据结构。队列会按照数据项出现的顺序来存储它们。队列是先进先出（FIFO）数据结构的实例。队列用 来对提交给操作系统或打印池的任务进行排序，而模拟应用程序则用队列对用户等待队列进行模拟。队列包含两种主要的操作。一个是给队列添加新的数据项，另一 个则是把数据项从队列中移除。添加新数据项的操作被称为是Enqueue，而从队列中移除数据项的操作则被称为是Dequeue。Enqueue 操作会在队列的末尾添加一个数据项，而Dequeue 操作则会从队列的
前端（或开始处）移除一个数据项。

（1）.Queue类。下面这个Queue 类的实现包含EnQueue 方法、DeQueue 方法、ClearQueue 方法（清除队列）、Peek 方法以及Count 方法，而且还有一个用于此类的默认构造器。

public class CQueue
{
     private ArrayList pqueue;
     public CQueue()
     {
          pqueue = new ArrayList();
     }
     public void EnQueue(object item)
     {
          pqueue.Add(item);
     }
     public void DeQueue()
     {
          pqueue.RemoveAt(0);
     }
     public object Peek()
     {
          return pqueue[0];
     }
     public void ClearQueue()
     {
          pqueue.Clear();
     }
     public int Count()
     {
          return pqueue.Count;
     }
}

（2）.Queue的应用

     1.几种初始化方式

        Queue myQueue = new Queue(100);

        Queue myQueue = new Queue(32, 3);

        Queue<int> numbers = new Queue<int>();

      2.实例应用

using System;
using System.Collections;
using System.IO ;
namespace csqueue
{
     public struct Dancer
     {
          public string name;
          public string sex;
          public void GetName(string n)
          {
               name = n;
          }
          public override string ToString()
          {
               return name;
     }
}
class Class1
{
     static void newDancers(Queue male, Queue female)
     {
          Dancer m, w;
          m = new Dancer();
          w = new Dancer();
          if (male.Count > 0 && female.Count > 0)
          {
               m.GetName(male.Dequeue().ToString());
               w.GetName(female.Dequeue().ToString());
          }
          else if ((male.Count > 0) && (female.Count == 0))
               Console.WriteLine("Waiting on a female dancer.");
          else if ((female.Count > 0) && (male.Count == 0))
               Console.WriteLine("Waiting on a male dancer.");
     }
     static void headOfLine(Queue male, Queue female)
     {
          Dancer w, m;
          m = new Dancer();
          w = new Dancer();
          if (male.Count > 0)
          m.GetName(male.Peek().ToString());
          if (female.Count > 0)
               w.GetName(female.Peek().ToString());
          if (m.name != " " && w.name != "")
               Console.WriteLine("Next in line are: " + m.name + "\t" + w.name);
          else
               if (m.name != "") //!=
                    Console.WriteLine("Next in line is: " + m.name);
               else
                    Console.WriteLine("Next in line is: " + w.name);
     }
     static void startDancing(Queue male, Queue female)
     {
          Dancer m, w;
          m = new Dancer();
          w = new Dancer();
          Console.WriteLine("Dance partners are: ");
          Console.WriteLine();
          for (int count = 0; count <= 3; count++)
          {
               m.GetName(male.Dequeue().ToString());
               w.GetName(female.Dequeue().ToString());
               Console.WriteLine(w.name + "\t" + m.name);
          }
     }
     static void formLines(Queue male, Queue female)
     {
          Dancer d = new Dancer();
          StreamReader inFile;
          inFile = File.OpenText(@"c:\dancers.dat");
          string line;
          while (inFile.Peek() != -1)
          {
               line = inFile.ReadLine();
               d.sex = line.Substring(0, 1);
               d.name = line.Substring(2, line.Length - 2);
               if (d.sex == "M")
                    male.Enqueue(d);
               else
                    female.Enqueue(d);
          }
     }
     static void Main(string[] args)
     {
          Queue males = new Queue();
          Queue females = new Queue();
          formLines(males, females);
          startDancing(males, females);
          if (males.Count > 0 || females.Count > 0)
               headOfLine(males, females);
          newDancers(males, females);
          if (males.Count > 0 || females.Count > 0)
               headOfLine(males, females);
          newDancers(males, females);
          Console.Write(" press enter");
          Console.Read();
     }
}