FIFO (First-In-First-Out) approach in Programming

FIFO is an abbreviation for first in, first out. It is a method for handling data structures where the first element is processed first and the newest element is processed last.

Real-life example:
 

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In this example, following things are to be considered: 

• There is a ticket counter where people come, take tickets and go.
• People enter a line (queue) to get to the Ticket Counter in an organized manner.
• The person to enter the queue first, will get the ticket first and leave the queue.
• The person entering the queue next will get the ticket after the person in front of him
• In this way, the person entering the queue last will the tickets last
• Therefore, the First person to enter the queue gets the ticket first and the Last person to enter the queue gets the ticket last.

This is known as First-In-First-Out approach or FIFO.

Where is FIFO used:

1. Data Structures:
   • Certain data structures like Queue and other variants of Queue uses FIFO approach for processing data. 
2. Disk scheduling:
   • Disk controllers can use the FIFO as a disk scheduling algorithm to determine the order in which to service disk I/O requests. 
3. Communications and networking"
   • Communication network bridges, switches and routers used in computer networks use FIFOs to hold data packets en route to their next destination.

Program Examples for FIFO

Program 1: Queue 

Elements of queue-0 1 2 3 4 
removed element-0
1 2 3 4 
head of queue-1
Size of queue-4

Complexities Analysis:

• Time Complexity: O(N)
• Space Complexity: O(N)