?What is the purpose of Software Development Life Cycle (SDLC) in Software Engineering

A sample waterfall life cycle model comprises the fallowing phases :

*Requirement analysis and specification :

Requirement analysis is usually the first phase of large-scale software development project. It is undertaken after a feasibility study  has been performed to define the precise costs and benefits of software system.

*System design and specification :

Once the requirements for a system have been documented , software engineers design a software system to meet them .

This phase is sometime split into two subphases : architectural or high-level design and detailed design . Architectural design entails defining the overall organization of the system in the terns of high-level components and interactions among them.

 *Coding and module testing :

in this phase, the engineer produce the actual code that will be delivered to the customer as the running system.

*Integration and system testing :

All the modules that have been developed before and tested individually are put together –integrated- in this phase and are tested as a whole system.

*Delivery and maintenance :

once the system passes all the tests , it is delivered to the customer and enters the maintenance phase. Any modification made to the system after the initial delivery are usually attributed this phase.