public int Pull()
{
if (head == null)
throw new NullReferenceException("head in null");
QueueElem tmp = head;
head = head.Next;
tmp.Next = null;
return tmp.Date;
}
public void Add(int date)
{
QueueElem newElem = new QueueElem();
newElem.Date = date;
if (end == null)
head = end = newElem;
else
{
end.Next = newElem;
end = newElem;
}
}