Stacks, Queues - LIFO, FIFO

LIFO( Last In First Out ) Principle of Stacks:

This strategy states that the element that is inserted last will come out first. You can take a pile of plates kept on top of each other as a real-life example. The plate which we put last is on the top and since we remove the plate that is at the top, we can say that the plate that was put last comes out first.

FIFO Principle of Queue:

A Queue is like a line waiting to purchase tickets, where the first person in line is the first person served. (i.e. First come first serve). Position of the entry in a queue ready to be served, that is, the first entry that will be removed from the queue, is called the front of the queue(sometimes, head of the queue), similarly, the position of the last entry in the queue, that is, the one most recently added, is called the rear (or the tail) of the queue.