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From The Collaborative International Dictionary of English v.0.44 [gcide]:
Recursion \Re*cur"sion\ (-sh?n), noun [L. recursio. See {Recur}.]
1. The act of recurring; return. [Obs.] --Boyle.
2. (Math.) The calculation of a mathematical expression (or a quantity) by repeating an operation on another expression which was derived by application of the same operation, on an expression which itself was the result of similar repeated applications of that same operation on prior results. The series of operations is terminated by specifying an initial or terminal condition.
3. (Computers) A programming technique in which a function calls itself as a subfunction. Such calls may be repeated in series to arbitrary depth, provided that a terminating condition is given so that the final (deepest) call will return a value (rather than continue to recurse), which then permits the next higher call to return a value, and so forth, until the original call returns a value to the calling program.
From WordNet (r) 2.0 [wn]:
recursion
noun: (mathematics) an expression such that each term is generated by repeating a particular mathematical operation
From Jargon File (4.3.1, 29 Jun 2001) [jargon]:
recursion n. See {recursion}. See also {tail recursion}.
From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:
recursion When a {function} (or {procedure}) calls itself. Such a function is called "recursive". If the call is via one or more other functions then this group of functions are called "mutually recursive". If a function will always call itself, however it is called, then it will never terminate. Usually however, it first performs some test on its arguments to check for a "base case" - a condition under which it can return a value without calling itself. The {canonical} example of a recursive function is {factorial}: factorial 0 = 1 factorial n = n * factorial (n-1) {Functional programming languages} rely heavily on recursion, using it where a {procedural language} would use {iteration}. See also {recursion}, {recursive definition}, {tail recursion}. [{Jargon File}] (1996-05-11)
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Definitions retrieved from local copies of the freely distributed DICT client/server software and databases. Click here for database copyright information. - KM |