SDLC is the process of planning, developing, testing, and deploying your software. This process consists of a sequence of phases, and each phase takes the outcome from the previous phase to proceed further. The following diagram depicts SDLC:

Let's understand each phase in detail:

• Requirement Analysis: This is the initial phase for problem analysis, where business analysts perform requirement analysis, and understand the business needs. The requirements can be internal to the organization or external from a customer. Requirements include the scope of the problem, which could either be for improving the system or building a new one, cost analysis, and project goals.
• Design: In this phase, the design for the implementation of the features of the software solution is prepared and approved. This includes process diagrams, documentations, layouts, and so on.
• Implementation: In this phase, actual implementation, based on the design, is carried out. Usually, developers develop the code depending on the goals defined in the design phase.
• Testing: In this phase, the developed code is tested by the QA (quality assurance) team under different scenarios. Each and every module is tested using unit testing as well as integration testing. In case of test failure, the developers are informed about the bug, and then they are required to fix it.
• Deployment/Release: In this phase, the tested feature is moved to production for customer review.
• Evolution: This phase gets the customer's review of the developed, tested, and published upgrades.