Diff for Recursion (computer science)

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== Recursion (computer science) ==

'''Recursion''' is a technique in [[computer science]] where a function calls itself, either directly or indirectly, in order to solve a problem by breaking it into smaller, similar subproblems. A recursive function typically consists of a ''base case'' (a condition that stops the recursion) and a ''recursive case'' (the part where the function calls itself with modified arguments). Recursion is widely used in [[algorithm]] design, [[data structures]], and [[functional programming]].

== Common examples ==

A classic example is the computation of the [[factorial]] of a number: the factorial of n (written n!) is defined as n × (n-1)!, with the base case 0! = 1. Another common example is the [[Fibonacci]] sequence, where each term is the sum of the two preceding terms, with base cases F(0)=0 and F(1)=1.

Recursion also naturally appears in operations on recursive data structures such as [[tree (data structure)|trees]] and [[linked list]]s, for tasks like tree traversal (e.g., depth-first search) and list processing.

== Features ==

* '''Elegance and simplicity''': Recursive solutions can express the problem's structure more directly than iterative approaches, making them easier to understand.
* '''Stack usage''': Each recursive call adds a new frame to the [[call stack]], which may lead to [[stack overflow]] if the recursion depth is too large.
* '''Tail recursion''': A special form where the recursive call is the last operation performed; some compilers and interpreters can optimize tail-recursive functions to avoid growing the stack ([[tail-call optimization]]).

== History ==

The concept of recursion in computing traces back to early work in [[computability theory]] and [[lambda calculus]] (developed by Alonzo Church in the 1930s), where recursive definitions were formalized. The first programming language to support recursion was [[Lisp (programming language)|Lisp]], introduced in the late 1950s. Recursion later became a cornerstone of [[functional programming]] languages and is supported in nearly all modern programming languages.

[[Category:Computer science]]
[[Category:Programming constructs]]
[[Category:Algorithms]]