The software development life cycle (SDLC) model is a solid approach to software development. The end product is actually achieved by putting some activities done in sequential order together. Enumerated latter are the various SDLC model phases. The first is the requirements, which determines the system's users, their major functionalities, the system's inputs and outputs. The second phase is design, which produces the look of the system in detail. The third phase is implementation; this implements the design process in form of code, and it is the lengthiest phase of the software development life cycle.
The last phase is the testing phase, which includes both system and unit texting. Texting is done to check if the code has been able to meet up with the functionalities required as designed from the requirements phase. Few models of SDLC include: spiral model, V-shaped model, incremental life cycle model, and waterfall model. Waterfall model is a stylish approach to the development of software, which follows a sequential and linear means of delivering software products.