Describe the functionality of a deque.

1.  A deque adds items to one side and remove items from the other side.
2.  A deque adds items to either or both sides, but only removes items from the top.
3.  A deque adds items at either or both ends, and remove items at either or both ends.
4.  A deque adds items only to the top, but remove from either or both sides.

Correct Answer:

•  A deque adds items at either or both ends, and remove items at either or both ends.

Explanation – deque is used to create block chanin and in that there is first in first out approch, which means the last element to enter will be the first to leave.