A queue is an ordered collection of items that follows the first in, first out (FIFO), also known as the first come, first served, principle. The addition of new elements in a queue is at the tail, and the removal is from the front. The newest element added to the queue must wait at the end of the queue.
The most popular example of a queue in real life is the typical line that we form from time to time:
We have lines for movies, the cafeteria, and a checkout line at a grocery store, among other examples. The first person in the line is the first one who will be attended to.
A very popular example in computer science ...
