"""
[::] in list means list[<start>:<stop>:<step>]
"""

"""
Abstract Data types: Imperative:(mutable data type)
            Functional:(immutable abstract data type)
"""


"""
ADT--> Stack(Recursive DS LIFO  as in built-in list used in Text Editors, Reversing the characters in string!)
ADT--> Queues (Recursive DS FIFO, order is preserved,so limited access.  adding item in queue is enqueue, removing means dequeue.
ADT--> Deque (Recursive DS LIFO+FIFO)
"""

