Software Development Life Cycle Methodologies
Published: 2020-12-03 16:57:17

**Software Development Life Cycle (SDLC)** is a process that is used to implement complex software systems. The goal of using SDLC is to produce high-quality software that meets customer expectations within a minimum time and cost. This approach is well defined and being used by almost every software development company.

Basically, SDLC consists of 6 phases. The cycle is completed iterating through these phases.

![Software Development Life Cycle](https://dev-to-uploads.s3.amazonaws.com/i/2t5iactlx0zb0m3e10ar.jpeg)

####Stage 1 — Planning
Requirement gathering and feasibility studies will be conducted in this stage by senior members of the team.

####Stage 2 — Defining
Product requirements will be clearly defined and documented in this stage. And this Software Requirement Specification (SRS) will be presented to the customer and get them approved.

####Stage 3 — Designing
Product architecture for the proposed product will be designed in this stage based on the SRS. Then the Design Document Specification (DDS) will be created.

####Stage 4 — Building
Actual development will be started at the stage. Developers will implement the system according to the DDS.

####Stage 5 — Testing
The developed product will be tested to check whether it meets the customer’s requirement and bugs and defects will be found and fixed in the program in this stage.

####Stage 6 — Deployment
The tested product will be released to the market and maintenance will be done.

After the deployment stage, customer feedback will be collected and the above cycle will be repeated for further releases.

###**SDLC Methodologies**

There are various SDLC models defined and designed based on SDLC. A few of them will be discussed here.

####1. Waterfall Model

![Waterfall Methodology](https://dev-to-uploads.s3.amazonaws.com/i/2sqry6hqhvaiekql1txp.png)

The waterfall model is the oldest SDLC model. This takes a linear structure the system requirements should be defined at the start and they cannot be changed during the process. Once the development is complete, the product will be tested against the initial requirements.

Present software development companies tend not to use this model since complex software systems need a more flexible development process. Once an application is in the testing stage, it is very difficult to go back and change something that was not well-documented or thought upon in the concept stage.

####2. Agile

![Agile Methodology](https://dev-to-uploads.s3.amazonaws.com/i/sf1uo5p9uwdhbrd36eau.jpeg)

This model is used in most organizations not only in the IT industry because agile methodology can be applied for other types of projects also. This approach produces ongoing release cycles with small, incremental changes from the previous release. The product is tested in each cycle. This method helps to find issues in the product early.

Many software development teams apply **scrum**, implementation of the agile framework for complex software systems.

####3. Spiral Model

![Spiral Methodology](https://dev-to-uploads.s3.amazonaws.com/i/z5um5tr12n48pb91t4oa.jpeg)

The spiral methodology allows the adoption of multiple SDLC models based on the risk patterns of the project. Projects that do not have clear requirements or expect major requirement changes during the development process can benefit from the scalability of this methodology. But the challenge is knowing when is the right moment to move on to the next phase with this model.

####4. V Model

![V Model](https://dev-to-uploads.s3.amazonaws.com/i/xsb4yt04np69hjr7eh5z.png)

V-Model is developed from the classic waterfall methodology. This model has a very strict approach, the next phase begins after the previous phase is completed. Since this lack of flexibility and higher-risk, this method is not suitable for complex software systems. But this is a good choice for projects whose requirements are clearly stated and static since the V model is easier to manage and control.


###**Choosing the best SDLC Model**

There is no best SDLC Model for all kinds of projects. This depends on several aspects.

* The complexity of the requirements
* Project duration
* Stakeholders concerns and priorities
* The development team and their skills