What is the use of SDLC in software engineering? code example

Example: what is SDLC

SDLC defines the phases in building of software or application.
o Project Planning
o Requirement Gathering (Gathering information used to plan project, 
Identifying risks)
o Design (How the application will be built)
o Coding (developing) (Based on requirements, 
developers will write the application)
o Testing
o Production (deployment)(Releasing product)
o Maintenance (Making sure product is stable, looking at 
customer report on bugs and fixing it)