C#实现顺序队列和链队列的代码实例

//自定义队列接口
namespace 队列
{
  interface IQueue
  {
    int Count { get; }
    int GetLength();
    bool IsEmpty();
    void Clear();
    void Enqueue(T item);
    T Dequeue();
    T Peek();
  }
}

//顺序队列的实现类
namespace 队列
{
  class SeqQueue : IQueue
  {
    private T[] data;
    private int count; //表示当前有几个元素
    private int front; //队首  （队首索引-1）
    private int rear;  //队尾 （队尾元素索引）
    public SeqQueue(int size)
    {
      data = new T[size];
      count = 0;
      front = -1;
      rear = -1;
    }
    public SeqQueue()
    {
      data = new T[10];
      count = 0;
      front = -1;
      rear = -1;
    }
    public int Count
    {
      get
      {
        return count;
      }
    }
    public void Clear()
    {
      count = 0;
      front = -1;
      rear = -1;
    }
    public T Dequeue()
    {
      if(count > 0)
      {
        T temp = data[front + 1];
        front++;
        count--;
        return temp;
      }
      else
      {
        Console.WriteLine("队列中没有数据，无法取得队首数据");
        return default(T);
      }
    }
    public void Enqueue(T item)
    {
      if (count == data.Length)
      {
        Console.WriteLine("队列元素已满，不可添加");
      }
      else
      {
        if (rear == data.Length -1) //最后一个位置是否有值
        {
          data[0] = item;
          rear = 0;
          count++;
        }
        else
        {
          data[rear + 1] = item;
          rear += 1;
          count++;
        }
      }
    }
    public int GetLength()
    {
      return count;
    }
    public bool IsEmpty()
    {
      return count == 0;
    }
    public T Peek()
    {
      T temp = data[front + 1];
      return temp;
    }
  }
}

//链队列的节点类
namespace 队列
{
  class Node {
    private T data;
    private Node next;
    public Node(T data)
    {
      this.data = data;
    }
    public T Data
    {
      get { return data; }
      set { data = value; }
    }
    public Node Next
    {
      get { return next; }
      set { next = value; }
    }
  }
}

//链队列的实现类
namespace 队列
{
  class LinkQueue : IQueue
  {
    private Node front; //头结点
    private Node rear; //尾结点
    private int count; //表示元素个数
    public LinkQueue()
    {
      front = null;
      rear = null;
      count = 0;
    }
    public int Count
    {
      get
      {
        return count;
      }
    }
    public void Clear()
    {
      front = null;
      rear = null;
      count = 0;
    }
    public T Dequeue()
    {
      if (count == 0)
      {
        Console.WriteLine("队列为空");
        return default(T);
      }else if(count == 1)
      {
        T temp = front.Data;
        front = rear = null;
        count = 0;
        return temp;
      }
      else
      {
        T temp = front.Data;
        front = front.Next;
        count--;
        return temp;
      }
    }
    public void Enqueue(T item)
    {
      Node newNode = new Node(item);
      if (count == 0)
      {
        front = newNode;
        rear = newNode;
        count = 1;
      }
      else
      {
        rear.Next = newNode;
        rear = newNode;
        count++;
      }
    }
    public int GetLength()
    {
      return count;
    }
    public bool IsEmpty()
    {
      return count == 0;
    }
    public T Peek()
    {
      if (front != null)
      {
        return front.Data;
      }
      else
      {
        return default(T);
      }
    }
  }
}

//以上两个实现类的测试类
namespace 队列
{
  class Program
  {
    static void Main(string[] args)
    {
      //CRL中的队列
      //Queue queue = new Queue();
      //自己的写的顺序队列
      //SeqQueue queue = new SeqQueue();
      //自己的链队列
      LinkQueue queue = new LinkQueue();
      queue.Enqueue(12);
      queue.Enqueue(34);
      queue.Enqueue(56);
      queue.Enqueue(78);
      queue.Enqueue(90);
      Console.WriteLine("添加五个元素后的大小："+ queue.Count);
      int i = queue.Dequeue();  //出队（取出并删除）
      Console.WriteLine("取出的元素是： " + i);
      Console.WriteLine("出队后队列大小：" + queue.Count);
      int j = queue.Peek();
      Console.WriteLine("Peek取出的元素是： " + j);
      Console.WriteLine("PeeK后队列大小：" + queue.Count);
      queue.Clear();
      Console.WriteLine("清空后的队列大小：" + queue.Count);
      Console.ReadKey();
    }
  }
}