public class Node          {              public int Data { get; set; }              public Node Next { get; set; }              public Node(int data)              {                  this.Data = data;              }          }     public class Queue          {              private Node _head;              private Node _tail;              private int _count = 0;                             public Queue() { }                 public void Enqueue(int data)              {                  Node _newNode = new Node(data);                  if (_head == null)                  {                      _head = _newNode;                      _tail = _head;                  }                  else                  {                      _tail.Next = _newNode;                      _tail = _tail.Next;                  }                  _count++;              }                 public int Dequeue()              {                  if (_head == null)                  {                      throw new Exception("Queue is Empty");                  }                  int _result = _head.Data;                  _head = _head.Next;                  return _result;              }                 public int Count              {                  get                  {                      return this._count;                  }              }          }