What do you mean by SDLC (Software Development Life Cycle)?

Many options exist for developing information systems. The most popular alternatives are structured analysis, which is a traditional method that is still used, object-oriented analysis (O-O), and agile methods.

Structured analysis uses a series of five phases, called the systems development life cycle (SDLC), to plan, analyze, design, implement, and support an information system.}is based on an overall plan, similar to a blueprint for constructing a building, so it is called a predictive approach.

The SDLC describes activities and functions that all systems developers perform, regardless of which approach they use. In the waterfall model, the result of each phase is called a deliverable, or end product, which flows into the next phase.A disadvantage in the built-in structure of the SDLC, is that the waterfall model does not emphasize interactivity among the phases. This criticism can be valid if the SDLC phases are followed too rigidly. However, adjacent phases usually interact.◦

SDLC  is a structure imposed on thedevelopment of a software product. Similar terms include software life cycle and software process

Software development  process 

1-Planning

2-mplementation, testing and documenting

2-Deployment and maintenance

Also note that there is also different model of  Software development such as : 

1-Spiral model

2-Waterdfall 

3-Agile development 

and mush  more 

SLDC is a process of how to develop software information systembased on some steps, this process describes planning, creation, testing and maintainance.

There are different SDLC models has been created based on one or more key features

(e.g. Waterfall, Spiral, and agile methodologies... )

I agree with the