Software development

Software development is the process of

Each of the available methodologies are best suited to specific kinds of projects, based on various technical, organizational, project, and team considerations.[3]

• The simplest methodology is the "code and fix", typically used by a single programmer working on a small project. After briefly considering the purpose of the program, the programmer codes it and runs it to see if it works. When they are done, the product is released. This methodology is useful for prototypes but cannot be used for more elaborate programs.^[4]
• In the top-down waterfall model, feasibility, analysis, design, development, quality assurance, and implementation occur sequentially in that order. This model requires one step to be complete before the next begins, causing delays, and makes it impossible to revise previous steps if necessary.^[5][6][7]
• With
  iterative processes these steps are interleaved with each other for improved flexibility, efficiency, and more realistic scheduling. Instead of completing the project all at once, one might go through most of the steps with one component at a time. Iterative development also lets developers prioritize the most important features, enabling lower priority ones to be dropped later on if necessary.^[6][8] Agile is one popular method, originally intended for small or medium sized projects, that focuses on giving developers more control over the features that they work on to reduce the risk of time or cost overruns.^[9] Derivatives of agile include extreme programming and Scrum.^[9] Open-source software development typically uses agile methodology with concurrent design, coding, and testing, due to reliance on a distributed network of volunteer contributors.^[10]
• Beyond agile, some companies integrate
  DevSecOps including computer security.^[11] DevOps includes continuous development, testing, integration of new code in the version control system, deployment of the new code, and sometimes delivery of the code to clients.^[12] The purpose of this integration is to deliver IT services more quickly and efficiently.^[11]

In 2009, it was estimated that 32 percent of software projects were delivered on time and budget, and with the full functionality. An additional 44 percent were delivered, but missing at least one of these features. The remaining 24 percent were cancelled prior to release.[14]

Design involves choices about the implementation of the software, such as which

The central feature of software development is creating and understanding the software that implements the desired functionality.^[26] There are various strategies for writing the code. Cohesive software has various components that are independent from each other.^[19] Coupling is the interrelation of different software components, which is viewed as undesirable because it increases the difficulty of maintenance.^[27] Often, software programmers do not follow industry best practices, resulting in code that is inefficient, difficult to understand, or lacking documentation on its functionality.^[28] These standards are especially likely to break down in the presence of deadlines.^[29] As a result, testing, debugging, and revising the code becomes much more difficult. Code refactoring, for example adding more comments to the code, is a solution to improve the understandability of code.^[30]

Testing is the process of ensuring that the code executes correctly and without errors.

Production is the phase in which software is deployed to the end user.^[34] During production, the developer may create technical support resources for users^[35][34] or a process for fixing bugs and errors that were not caught earlier. There might also be a return to earlier development phases if user needs changed or were misunderstood.^[34]

Software development is performed by software developers, usually working on a team. Efficient communications between team members is essential to success. This is more easily achieved if the team is small, used to working together, and located near each other.^[36] Communications also help identify problems at an earlier state of development and avoid duplicated effort. Many development projects avoid the risk of losing essential knowledge held by only one employee by ensuring that multiple workers are familiar with each component.^[37] Software development involves professionals from various fields, not just software programmers but also individuals specialized in testing, documentation writing, graphic design, user support, marketing, and fundraising. Although workers for proprietary software are paid, most contributors to open-source software are volunteers.^[38] Alternately, they may be paid by companies whose business model does not involve selling the software, but something else—such as services and modifications to open source software.^[39]

Documentation comes in two forms that are usually kept separate—that intended for software developers, and that made available to the end user to help them use the software.

Accurate estimation is crucial at the feasibility stage and in delivering the product on time and within budget. The process of generating estimations is often delegated by the

An

Version control is a popular way of managing changes made to the software. Whenever a new version is checked in, the software saves a backup of all modified files. If multiple programmers are working on the software simultaneously, it manages the merging of their code changes. The software highlights cases where there is a conflict between two sets of changes and allows programmers to fix the conflict.^[54]

A view model is a framework that provides the viewpoints on the system and its environment, to be used in the software development process. It is a graphical representation of the underlying semantics of a view.

The purpose of viewpoints and views is to enable human engineers to comprehend very

Fitness functions are automated and objective tests to ensure that the new developments don't deviate from the established constraints, checks and compliance controls.^[56]