In this unit, we described about the data structure Queue. It had two ends. One is front from where the elements can be removed and the other is rear where the elements can be inserted. A queue can be implemented via Arrays or Linked lists. Each illustration is having it's own advantages & disadvantages. The problems along arrays are that they are restricted in space. Therefore, the queue is having a restricted capacity. If queues are implemented via linked lists, then this problem is solved. Now, there is no restriction on the capacity of the queue. The only overhead is the memory occupied though the pointers.

There are a number of variants of the queues. Queues normally mean circular queues. In spite of linear queues, we also discussed circular queues in this unit. A particular type of queue called Dequeue was also discussed in this unit. Dequeues allows elements to be inserted or deleted at either of the rear or front. We also discussed the array & linked list implementations of Dequeue.