Computer programming (often shortened to programming) is a process that leads from an original formulation of a computing problem to executable computer programs.
Programming involves activities such as analysis, developing understanding, generating algorithms, verification of requirements of algorithms including their correctness and resources consumption, and implementation (commonly referred to as coding) of algorithms in a target programming language.
Source code is written in one or more programming languages. The purpose of programming is to find a sequence of instructions that will automate performing a specific task or solving a given problem. The process of programming thus often requires expertise in many different subjects, including knowledge of the application domain, specialized algorithms, and formal logic.
Related tasks include testing, debugging, and maintaining the source code, implementation of the build system, and management of derived artifacts such as machine code of computer programs. These might be considered part of the programming process, but often the term software development is used for this larger process with the term programming, implementation, or coding reserved for the actual writing of source code.
Software engineering combines engineering techniques with software development practices.
Different programming languages support different styles of programming (called programming paradigms). The choice of language used is subject to many considerations, such as company policy, suitability to task, availability of third-party packages, or individual preference. Ideally, the programming language best suited for the task at hand will be selected. Trade-offs from this ideal involve finding enough programmers who know the language to build a team, the availability of compilers for that language, and the efficiency with which programs written in a given language execute. Languages form an approximate spectrum from “low-level” to “high-level”; “low-level” languages are typically more machine-oriented and faster to execute, whereas “high-level” languages are more abstract and easier to use but execute less quickly. It is usually easier to code in “high-level” languages than in “low-level” ones.
Allen Downey, in his book How To Think Like A Computer Scientist, writes:
- The details look different in different languages, but a few basic instructions appear in just about every language:
- Input: Gather data from the keyboard, a file, or some other device.
- Output: Display data on the screen or send data to a file or other device.
- Arithmetic: Perform basic arithmetical operations like addition and multiplication.
- Conditional Execution: Check for certain conditions and execute the appropriate sequence of statements.
- Repetition: Perform some action repeatedly, usually with some variation.
Many computer languages provide a mechanism to call functions provided by shared libraries. Provided the functions in a library follow the appropriate run-time conventions (e.g., method of passing arguments), then these functions may be written in any other language.
Computer programmers are those who write computer software. Their jobs usually involve: