Software design pattern

In software engineering, a software design pattern or design pattern is a general, reusable solution to a commonly occurring problem in many contexts in software design.^[1] A design pattern is not a rigid structure to be transplanted directly into source code. Rather, it is a description or a template for solving a particular type of problem that can be deployed in many different situations.^[2] Design patterns can be viewed as formalized best practices that the programmer may use to solve common problems when designing a software application or system.

Object-oriented design patterns typically show relationships and interactions between classes or objects, without specifying the final application classes or objects that are involved.^{[citation needed]} Patterns that imply mutable state may be unsuited for functional programming languages. Some patterns can be rendered unnecessary in languages that have built-in support for solving the problem they are trying to solve, and object-oriented patterns are not necessarily suitable for non-object-oriented languages.^{[citation needed]}

Design patterns may be viewed as a structured approach to computer programming intermediate between the levels of a programming paradigm and a concrete algorithm.^{[citation needed]}