Queue
It stores the list of items in which an item can be inserted at one end and removed from other end only.
It is based on FIFO (First In First Out) mechanism.
Operations
This includes:
1. enqueue(x) - This is same as push that was in stack.
2. dequeue() - This is same as pop that was in stack.
3. peek() - It will return the element corresponding to front.
4. empty() - Checks whether the queue is empty or not.
