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| {{Redirect|XOR|the logic gate|XOR gate|other uses|XOR (disambiguation)}}
| | This is a preview for the new '''MathML rendering mode''' (with SVG fallback), which is availble in production for registered users. |
| {{Refimprove|date=January 2012}}
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| {| style="background: #f9f9f9; border: 1px solid #cccccc;" align="right"
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| | [[File:Venn0110.svg|220px]]
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| | [[Venn diagram]] of <math>\scriptstyle A \oplus B</math><br>
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| [[File:Venn0111.svg|35px|OR]] but not [[File:Venn0001.svg|35px|AND]] is [[File:Venn0110.svg|35px|XOR]]
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| | [[File:Venn 0110 1001.svg|220px]]
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| | [[Venn diagram]] of <math>\scriptstyle A \oplus B \oplus C</math><br>
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| [[File:Venn 0110 0110.svg|40px]] <math>~\oplus~</math> [[File:Venn 0000 1111.svg|40px]] <math>~\Leftrightarrow~</math> [[File:Venn 0110 1001.svg|40px]]
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| |}
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| The [[Logical connective|logical operation]] '''exclusive disjunction''', also called '''exclusive or''' ([[Table of logic symbols|symbolized]] by the prefix operator '''J''', or by the infix operators '''XOR''', '''EOR''', '''EXOR''', '''<font size="4">⊻</font>''' or '''<font size="5">⊕</font>''', {{IPAc-en|icon|ˌ|ɛ|k|s|_|ˈ|ɔr}} or {{IPAc-en|ˈ|z|ɔr}}), is a type of [[logical disjunction]] on two [[operands]] that results in a value of [[Boolean_data_type|true]] if exactly one of the operands has a value of true.<ref>See ''[[Stanford Encyclopedia of Philosophy]]'', article ''[http://plato.stanford.edu/entries/disjunction/ Disjunction]''</ref> A simple way to state this is "one or the other but not both."
| | If you would like use the '''MathML''' rendering mode, you need a wikipedia user account that can be registered here [[https://en.wikipedia.org/wiki/Special:UserLogin/signup]] |
| | * Only registered users will be able to execute this rendering mode. |
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| Put differently, exclusive disjunction is a logical operation on two [[logical value]]s, typically the values of two [[proposition]]s, that produces a value of ''true'' only in cases where the [[truth value]] of the operands differ.
| | Registered users will be able to choose between the following three rendering modes: |
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| The opposite of XOR is [[logical biconditional]], where the output of two compared values is true only if both A and B are the same.
| | '''MathML''' |
| | :<math forcemathmode="mathml">E=mc^2</math> |
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| ==Truth table==
| | <!--'''PNG''' (currently default in production) |
| [[File:Multigrade operator XOR.svg|thumb|220px|Arguments on the left combined by XOR<br>This is a binary [[Walsh matrix]]<br>(compare: [[Hadamard code]])]]
| | :<math forcemathmode="png">E=mc^2</math> |
| The [[truth table]] of <math>~A \oplus B</math> (also written as <math>A\, \mathrm{XOR}\, B</math> or <math>A \neq B</math>) is as follows:
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| {| class="wikitable" style="text-align:center"
| | '''source''' |
| |+ XOR Truth Table
| | :<math forcemathmode="source">E=mc^2</math> --> |
| |-
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| !colspan="2" | Input || rowspan="2" | Output
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| |-
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| !A || B
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| |-
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| | 0 || 0 || 0
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| |-
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| | 0 || 1 || 1
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| |-
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| | 1 || 0 || 1
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| |-
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| | 1 || 1 || 0
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| |}
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| ==Equivalencies, elimination, and introduction== | | <span style="color: red">Follow this [https://en.wikipedia.org/wiki/Special:Preferences#mw-prefsection-rendering link] to change your Math rendering settings.</span> You can also add a [https://en.wikipedia.org/wiki/Special:Preferences#mw-prefsection-rendering-skin Custom CSS] to force the MathML/SVG rendering or select different font families. See [https://www.mediawiki.org/wiki/Extension:Math#CSS_for_the_MathML_with_SVG_fallback_mode these examples]. |
| Exclusive disjunction essentially means 'either one, but not both'. In other words, [[if and only if]] one is true, the other cannot be true. For example, one of the two horses will win the race, but not both of them. The exclusive disjunction :<math>p \oplus q</math>, or J''pq'', can be expressed in terms of the [[logical conjunction]] (<math>\wedge</math>), the [[disjunction]] (<math>\lor</math>), and the [[negation]] (<math>\lnot</math>) as follows:
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| : <math>\begin{matrix}
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| p \oplus q & = & (p \land \lnot q) \lor (\lnot p \land q)
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| \end{matrix}</math>
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| The exclusive disjunction <math>p \oplus q</math> can also be expressed in the following way:
| | ==Demos== |
| : <math>\begin{matrix}
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| p \oplus q & = & \lnot (p \land q) \land (p \lor q)
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| \end{matrix}</math>
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| This representation of XOR may be found useful when constructing a circuit or network, because it has only one <math>\lnot</math> operation and small number of <math>\wedge</math> and <math>\lor</math> operations. The proof of this identity is given below:
| | Here are some [https://commons.wikimedia.org/w/index.php?title=Special:ListFiles/Frederic.wang demos]: |
| : <math>\begin{matrix} | |
| p \oplus q & = & (p \land \lnot q) & \lor & (\lnot p \land q) \\
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| & = & ((p \land \lnot q) \lor \lnot p) & \and & ((p \land \lnot q) \lor q) \\
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| & = & ((p \lor \lnot p) \land (\lnot q \lor \lnot p)) & \land & ((p \lor q) \land (\lnot q \lor q)) \\
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| & = & (\lnot p \lor \lnot q) & \land & (p \lor q) \\
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| & = & \lnot (p \land q) & \land & (p \lor q)
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| \end{matrix}</math>
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| It is sometimes useful to write <math>p \oplus q</math> in the following way:
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| : <math>\begin{matrix}
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| p \oplus q & = & \lnot ((p \land q) \lor (\lnot p \land \lnot q))
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| \end{matrix}</math>
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| This equivalence can be established by applying [[De Morgan's laws]] twice to the fourth line of the above proof.
| | * accessibility: |
| | ** Safari + VoiceOver: [https://commons.wikimedia.org/wiki/File:VoiceOver-Mac-Safari.ogv video only], [[File:Voiceover-mathml-example-1.wav|thumb|Voiceover-mathml-example-1]], [[File:Voiceover-mathml-example-2.wav|thumb|Voiceover-mathml-example-2]], [[File:Voiceover-mathml-example-3.wav|thumb|Voiceover-mathml-example-3]], [[File:Voiceover-mathml-example-4.wav|thumb|Voiceover-mathml-example-4]], [[File:Voiceover-mathml-example-5.wav|thumb|Voiceover-mathml-example-5]], [[File:Voiceover-mathml-example-6.wav|thumb|Voiceover-mathml-example-6]], [[File:Voiceover-mathml-example-7.wav|thumb|Voiceover-mathml-example-7]] |
| | ** [https://commons.wikimedia.org/wiki/File:MathPlayer-Audio-Windows7-InternetExplorer.ogg Internet Explorer + MathPlayer (audio)] |
| | ** [https://commons.wikimedia.org/wiki/File:MathPlayer-SynchronizedHighlighting-WIndows7-InternetExplorer.png Internet Explorer + MathPlayer (synchronized highlighting)] |
| | ** [https://commons.wikimedia.org/wiki/File:MathPlayer-Braille-Windows7-InternetExplorer.png Internet Explorer + MathPlayer (braille)] |
| | ** NVDA+MathPlayer: [[File:Nvda-mathml-example-1.wav|thumb|Nvda-mathml-example-1]], [[File:Nvda-mathml-example-2.wav|thumb|Nvda-mathml-example-2]], [[File:Nvda-mathml-example-3.wav|thumb|Nvda-mathml-example-3]], [[File:Nvda-mathml-example-4.wav|thumb|Nvda-mathml-example-4]], [[File:Nvda-mathml-example-5.wav|thumb|Nvda-mathml-example-5]], [[File:Nvda-mathml-example-6.wav|thumb|Nvda-mathml-example-6]], [[File:Nvda-mathml-example-7.wav|thumb|Nvda-mathml-example-7]]. |
| | ** Orca: There is ongoing work, but no support at all at the moment [[File:Orca-mathml-example-1.wav|thumb|Orca-mathml-example-1]], [[File:Orca-mathml-example-2.wav|thumb|Orca-mathml-example-2]], [[File:Orca-mathml-example-3.wav|thumb|Orca-mathml-example-3]], [[File:Orca-mathml-example-4.wav|thumb|Orca-mathml-example-4]], [[File:Orca-mathml-example-5.wav|thumb|Orca-mathml-example-5]], [[File:Orca-mathml-example-6.wav|thumb|Orca-mathml-example-6]], [[File:Orca-mathml-example-7.wav|thumb|Orca-mathml-example-7]]. |
| | ** From our testing, ChromeVox and JAWS are not able to read the formulas generated by the MathML mode. |
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| The exclusive or is also equivalent to the negation of a [[logical biconditional]], by the rules of material implication (a [[material conditional]] is equivalent to the disjunction of the negation of its [[Antecedent (logic)|antecedent]] and its consequence) and [[If and only if|material equivalence]].
| | ==Test pages == |
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| In summary, we have, in mathematical and in engineering notation:
| | To test the '''MathML''', '''PNG''', and '''source''' rendering modes, please go to one of the following test pages: |
| : <math>\begin{matrix} | | *[[Displaystyle]] |
| p \oplus q & = & (p \land \lnot q) & \lor & (\lnot p \land q) & = & p\overline{q} + \overline{p}q \\
| | *[[MathAxisAlignment]] |
| \\
| | *[[Styling]] |
| & = & (p \lor q) & \land & (\lnot p \lor \lnot q) & = & (p+q)(\overline{p}+\overline{q}) \\
| | *[[Linebreaking]] |
| \\
| | *[[Unique Ids]] |
| & = & (p \lor q) & \land & \lnot (p \land q) & = & (p+q)(\overline{pq})
| | *[[Help:Formula]] |
| \end{matrix}</math>
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| ==Relation to modern algebra==
| | *[[Inputtypes|Inputtypes (private Wikis only)]] |
| | | *[[Url2Image|Url2Image (private Wikis only)]] |
| Although the [[Operation (mathematics)|operators]] <math>\wedge</math> ([[Logical conjunction|conjunction]]) and <math>\lor</math> ([[Logical disjunction|disjunction]]) are very useful in logic systems, they fail a more generalizable structure in the following way:
| | ==Bug reporting== |
| | | If you find any bugs, please report them at [https://bugzilla.wikimedia.org/enter_bug.cgi?product=MediaWiki%20extensions&component=Math&version=master&short_desc=Math-preview%20rendering%20problem Bugzilla], or write an email to math_bugs (at) ckurs (dot) de . |
| The systems <math>(\{T, F\}, \wedge)</math> and <math>(\{T, F\}, \lor)</math> are [[monoid]]s. This unfortunately prevents the combination of these two systems into larger structures, such as a [[Ring (mathematics)|mathematical ring]].
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| However, the system using exclusive or <math>(\{T, F\}, \oplus)</math> '''is''' an [[abelian group]]. The combination of operators <math>\wedge</math> and <math>\oplus</math> over elements <math>\{T, F\}</math> produce the well-known [[field (mathematics)|field]] [[GF(2)|<math>F_2</math>]]. This field can represent any logic obtainable with the system <math>(\land, \lor)</math> and has the added benefit of the arsenal of algebraic analysis tools for fields.
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| More specifically, if one associates <math>F</math> with 0 and <math>T</math> with 1, one can interpret the logical "AND" operation as multiplication on <math>F_2</math> and the "XOR" operation as addition on <math>F_2</math>:
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| <math>\begin{matrix}
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| r = p \land q & \Leftrightarrow & r = p \cdot q \pmod 2 \\
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| \\
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| r = p \oplus q & \Leftrightarrow & r = p + q \pmod 2 \\
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| \end{matrix}</math>
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| Using this basis to describe a boolean system is referred to as [[algebraic normal form]]
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| ==Exclusive "or" in English==
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| The Oxford English Dictionary explains "either ... or" as follows:
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| :"The primary function of ''either'', etc., is to emphasize the [[Mutually independent|perfect indifference]] of the two (or more) things or courses ... ; but a secondary function is to emphasize the mutual exclusiveness, = either of the two, but not both."<ref>or, conj.2 (adv.3) 2a ''Oxford English Dictionary'', second edition (1989). OED Online.</ref>
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| The exclusive-or explicitly states "one or the other, but not neither nor both."
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| Following this kind of common-sense intuition about "or", it is sometimes argued that in many natural languages, [[English language|English]] included, the word "or" has an "exclusive" sense. The '''exclusive disjunction''' of a pair of propositions, (''p'', ''q''), is supposed to mean that ''p'' is true or ''q'' is true, but not both. For example, it might be argued that the normal intention of a statement like "You may have coffee, or you may have tea" is to stipulate that exactly one of the conditions can be true. Certainly under many circumstances a sentence like this example should be taken as forbidding the possibility of one's accepting both options. Even so, there is good reason to suppose that this sort of sentence is not disjunctive at all. If all we know about some disjunction is that it is true overall, we cannot be sure that either of its disjuncts is true. For example, if a woman has been told that her friend is either at the snack bar or on the tennis court, she cannot validly infer that he is on the tennis court. But if her waiter tells her that she may have coffee or she may have tea, she can validly infer that she may have tea. Nothing classically thought of as a disjunction has this property. This is so even given that she might reasonably take her waiter as having denied her the possibility of having both coffee and tea.{{cn|date=June 2012}}
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| (Note: If the waiter intends that choosing neither tea nor coffee is an option i.e. ordering nothing, the appropriate operator is [[logical NAND|NAND]]: p NAND q.)
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| In English, the construct "either ... or" is usually used to indicate exclusive or and "or" generally used for inclusive. But in Spanish, the word "o" (or) can be used in the form p o q (exclusive) or the form o p o q (inclusive). Formalists may contend that any binary or other [[arity|n-ary]] exclusive "or" is true if and only if it has an odd number of true inputs, and there is no word in English that can conjoin a list of two or more options has this general property. For example, Barrett and Stenner contend in the 1971 article "The Myth of the Exclusive 'Or{{' "}} (Mind, 80 (317), 116–121) that no author has produced an example of an English or-sentence that appears to be false because both of its inputs are true, and brush off or-sentences such as "The light bulb is either on or off" as reflecting particular facts about the world rather than the nature of the word "or". However, the "[[barber paradox]]" -- Everybody in town shaves himself or is shaved by the barber, who shaves the barber? -- would not be paradoxical if "or" could not be exclusive (although a purist could say that "either" is required in the statement of the paradox).
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| Whether these examples can be considered "natural language" is another question. Certainly when one sees a menu stating "Lunch special: sandwich and soup or salad" (parsed as "sandwich and (soup or salad)" according to common usage in the restaurant trade), one would not expect to be permitted to order both soup and salad. Nor would one expect to order neither soup nor salad, because that belies the nature of the "special", that ordering the two items together is cheaper than ordering them a la carte. Similarly, a lunch special consisting of one meat, French fries or mashed potatoes and vegetable would consist of three items, only one of which would be a form of potato. If one wanted to have meat and both kinds of potatoes, one would ask if it were possible to substitute a second order of potatoes for the vegetable. And, one would not expect to be permitted to have both types of potato and vegetable, because the result would be a vegetable plate rather than a meat plate.{{cn|date=June 2012}}
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| ==Alternative symbols==
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| The symbol used for exclusive disjunction varies from one field of application to the next, and even depends on the properties being emphasized in a given context of discussion. In addition to the abbreviation "XOR", any of the following symbols may also be seen:
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| * A plus sign (+). This makes sense mathematically because exclusive disjunction corresponds to [[addition]] [[modular arithmetic|modulo]] 2, which has the following addition table, clearly [[isomorphism|isomorphic]] to the one above:
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| {| align="center" class="wikitable" style="text-align:center; text-align:center; width:45%"
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| |+ '''Addition Modulo 2'''
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| |- style="background:paleturquoise"
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| ! style="width:15%" | <math>p</math>
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| ! style="width:15%" | <math>q</math>
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| ! style="width:15%" | <math>p + q</math>
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| |-
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| | 0 || 0 || 0
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| |-
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| | 0 || 1 || 1
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| |-
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| | 1 || 0 || 1
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| |-
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| | 1 || 1 || 0
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| |}
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| * The use of the plus sign has the added advantage that all of the ordinary algebraic properties of mathematical [[ring (mathematics)|rings]] and [[field (mathematics)|fields]] can be used without further ado. However, the plus sign is also used for Inclusive disjunction in some notation systems.
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| * A plus sign that is modified in some way, such as being encircled (<math>\oplus</math>). This usage faces the objection that this same symbol is already used in mathematics for the ''[[Direct sum of modules|direct sum]]'' of algebraic structures.
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| * A prefixed J, as in J''pq''.
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| * An inclusive disjunction symbol (<math>\lor</math>) that is modified in some way, such as being underlined (<math>\underline\lor</math>) or with dot above (<math>\dot\vee</math>).
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| * In several [[programming language]]s, such as [[C (programming language)|C]], [[C++]], [[C Sharp (programming language)|C#]], [[Java (programming language)|Java]], [[Perl]], [[MATLAB]], and [[Python (programming language)|Python]], a [[caret]] (<code>^</code>) is used to denote the bitwise XOR operator. This is not used outside of programming contexts because it is too easily confused with other uses of the caret.
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| * The symbol [[File:X-or.svg|24px]], sometimes written as >< or as >-<.
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| * In IEC symbology, an exclusive or is marked "=1".
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| ==Properties==
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| '''[[Commutative property|Commutativity]]: yes'''
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| {| style="text-align: center; border: 1px solid darkgray;"
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| |-
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| |<math>A \oplus B</math>
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| | <math>\Leftrightarrow</math>
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| |<math>B \oplus A</math>
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| |-
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| |[[File:Venn0110.svg|50px]]
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| | <math>\Leftrightarrow</math>
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| |[[File:Venn0110.svg|50px]]
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| |}
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| '''[[Associative property|Associativity]]: yes'''
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| {| style="text-align: center; border: 1px solid darkgray;"
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| |-
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| |<math>~A</math>
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| |<math>~~~\oplus~~~</math>
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| |<math>(B \oplus C)</math>
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| | <math>\Leftrightarrow</math>
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| |<math>(A \oplus B)</math>
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| |<math>~~~\oplus~~~</math>
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| |<math>~C</math>
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| |-
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| |[[File:Venn 0101 0101.svg|50px]]
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| |<math>~~~\oplus~~~</math>
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| |[[File:Venn 0011 1100.svg|50px]]
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| | <math>\Leftrightarrow</math>
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| |[[File:Venn 0110 1001.svg|50px]]
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| | <math>\Leftrightarrow</math>
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| |[[File:Venn 0110 0110.svg|50px]]
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| |<math>~~~\oplus~~~</math>
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| |[[File:Venn 0000 1111.svg|50px]]
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| |}
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| '''[[Distributive property|Distributivity]]:''' The exclusive or doesn't distribute over any binary function (not even itself),<br>
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| but logical conjunction (see [[Logical_conjunction#Properties|there]]) distributes over exclusive or.<br>
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| (Conjunction and exclusive or form the multiplication and addition operations of a [[Field_(mathematics)|field]] [[GF(2)]], and as in any field they obey the distributive law.)
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| '''[[Idempotence|Idempotency]]: no'''<br>
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| {| style="text-align: center; border: 1px solid darkgray;"
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| |-
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| |<math>~A~</math>
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| |<math>~\oplus~</math>
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| |<math>~A~</math>
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| | <math>\Leftrightarrow</math>
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| |<math>~0~</math>
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| | <math>\nLeftrightarrow</math>
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| |<math>~A~</math>
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| |-
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| |[[File:Venn01.svg|36px]]
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| |<math>~\oplus~</math>
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| |[[File:Venn01.svg|36px]]
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| | <math>\Leftrightarrow</math>
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| |[[File:Venn00.svg|36px]]
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| | <math>\nLeftrightarrow</math>
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| |[[File:Venn01.svg|36px]]
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| |}
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| '''[[Monotonic function#Boolean_functions|Monotonicity]]: no'''
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| {| style="text-align: center; border: 1px solid darkgray;"
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| |<math>A \rightarrow B</math>
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| | <math>\nRightarrow</math>
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| |<math>(A \oplus C)</math>
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| |<math>\rightarrow</math>
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| |<math>(B \oplus C)</math>
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| |-
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| ||[[File:Venn 1011 1011.svg|50px]]
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| | <math>\nRightarrow</math>
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| ||[[File:Venn 1011 1101.svg|50px]]
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| | <math>\Leftrightarrow</math>
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| ||[[File:Venn 0101 1010.svg|50px]]
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| |<math>\rightarrow</math>
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| ||[[File:Venn 0011 1100.svg|50px]]
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| |}
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| '''Truth-preserving: no'''<br>
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| When all inputs are true, the output is not true.
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| {| style="text-align: center; border: 1px solid darkgray;"
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| |-
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| |<math>A \and B</math>
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| | <math>\nRightarrow</math>
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| |<math>A \oplus B</math>
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| |-
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| |[[File:Venn0001.svg|50px]]
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| | <math>\nRightarrow</math>
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| |[[File:Venn0110.svg|60px]]
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| |}
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| '''Falsehood-preserving: yes'''<br>
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| When all inputs are false, the output is false.
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| {| style="text-align: center; border: 1px solid darkgray;"
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| |-
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| |<math>A \oplus B</math>
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| | <math>\Rightarrow</math>
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| |<math>A \or B</math>
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| |-
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| |[[File:Venn0110.svg|60px]]
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| | <math>\Rightarrow</math>
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| |[[File:Venn0111.svg|50px]]
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| |}
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| '''[[Hadamard transform|Walsh spectrum]]: (2,0,0,-2)'''
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| '''Non-[[Linear#Boolean functions|linearity]]: 0''' (the function is linear)
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| If using [[binary numeral system|binary]] values for true (1) and false (0), then ''exclusive or'' works exactly like [[addition]] [[Modular arithmetic|modulo]] 2.
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| ==Computer science==
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| [[File:XOR ANSI Labelled.svg|thumb|right|114px|Traditional symbolic representation of an XOR [[logic gate]]]]
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| ===Bitwise operation===
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| {{Main|Bitwise operation}}
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| [[File:Z2^4; Cayley table; binary.svg|thumb|[[Nimber]] addition is the ''exclusive or'' of [[natural number|nonnegative integers]] in [[w:binary numeral system|binary]] representation. This is also the vector addition in <math>(\Z/2\Z)^4</math>.]]
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| Exclusive disjunction is often used for bitwise operations. Examples:
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| * 1 xor 1 = 0
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| * 1 xor 0 = 1
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| * 0 xor 1 = 1
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| * 0 xor 0 = 0
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| * 1110 xor 1001 = 0111 (this is equivalent to addition without [[carry (arithmetic)|carry]])
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| As noted above, since exclusive disjunction is identical to addition modulo 2, the bitwise exclusive disjunction of two ''n''-bit strings is identical to the standard vector of addition in the [[vector space]] <math>(\Z/2\Z)^n</math>.
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| In computer science, exclusive disjunction has several uses:
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| * It tells whether two bits are unequal.
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| * It is an optional bit-flipper (the deciding input chooses whether to invert the data input).
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| * It tells whether there is an [[Parity (mathematics)|odd]] number of 1 bits (<math>A \oplus B \oplus C \oplus D \oplus E</math> is true [[If and only if|iff]] an odd number of the variables are true).
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| In logical circuits, a simple [[adder (electronics)|adder]] can be made with an [[XOR gate]] to add the numbers, and a series of AND, OR and NOT gates to create the carry output.
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| On some computer architectures, it is more efficient to store a zero in a register by xor-ing the register with itself (bits xor-ed with themselves are always zero) instead of loading and storing the value zero.
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| In simple threshold activated [[neural network]]s, modeling the 'xor' function requires a second layer because 'xor' is not a linearly separable function.
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| Exclusive-or is sometimes used as a simple mixing function in [[cryptography]], for example, with [[one-time pad]] or [[Feistel cipher|Feistel network]] systems.
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| Similarly, XOR can be used in generating [[entropy pool]]s for [[hardware random number generator]]s. The XOR operation preserves randomness, meaning that a random bit XORed with a non-random bit will result in a random bit. Multiple sources of potentially random data can be combined using XOR, and the unpredictability of the output is guaranteed to be at least as good as the best individual source.<ref>http://www.digipedia.pl/usenet/thread/11834/2075/</ref><ref>http://www.robertnz.net/pdf/xor2.pdf</ref>
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| XOR is used in [[RAID]] 3–6 for creating parity information. For example, RAID can "back up" bytes <code>10011100</code> and <code>01101100</code> from two (or more) hard drives by XORing (<code>11110000</code>) and writing to another drive. Under this method, if any one of the three hard drives are lost, the lost byte can be re-created by XORing bytes from the remaining drives. If the drive containing <code>01101100</code> is lost, <code>10011100</code> and <code>11110000</code> can be XORed to recover the lost byte.
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| XOR is also used to detect an overflow in the result of a signed binary arithmetic operation. If the leftmost retained bit of the result is not the same as the infinite number of digits to the left, then that means overflow occurred. XORing those two bits will give a "1" if there is an overflow.
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| XOR can be used to swap two numeric variables in computers, using the [[XOR swap algorithm]]; however this is regarded as more of a curiosity and not encouraged in practice.
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| In [[computer graphics]], XOR-based drawing methods are often used to manage such items as [[bounding volume|bounding boxes]] and [[cursor (computers)|cursors]] on systems without [[alpha compositing|alpha channels]] or overlay planes.
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| ==See also==
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| {{col-begin}}
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| {{col-break|width=33%}}
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| * [[Affirming a disjunct]]
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| * [[Ampheck]]
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| * [[Boolean algebra (logic)]]
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| * [[List of Boolean algebra topics]]
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| * [[Boolean domain]]
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| * [[Boolean function]]
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| * [[Boolean-valued function]]
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| * [[Controlled NOT gate]]
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| * [[Disjunctive syllogism]]
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| {{col-break|width=33%}}
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| * [[First-order logic]]
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| * [[Inclusive or]]
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| * [[involution (mathematics)|Involution]]
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| * [[Logical graph]]
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| * [[Logical value]]
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| * [[Multigrade operator]]
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| * [[Operation (mathematics)|Operation]]
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| {{col-break}}
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| * [[Parametric operator]]
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| * [[Parity bit]]
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| * [[Propositional calculus]]
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| * [[Rule 90]]
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| * [[Symmetric difference]]
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| * [[XOR linked list]]
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| * [[XOR gate]]
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| * [[XOR cipher]]
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| {{col-end}}
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| ==Notes==
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| <references/>
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| {{Logical connectives}}
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| ==External links==
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| *[http://www.codeplex.com/rexor An example of XOR being used in cryptography]
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| [[Category:Logic]]
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| [[Category:Boolean algebra]]
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| [[Category:Binary operations]]
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| [[Category:Propositional calculus]]
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| [[Category:Logical connectives]]
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| [[ca:Disjunció exclusiva]]
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| [[cs:Exkluzivní disjunkce]]
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| [[de:Kontravalenz]]
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| [[et:Välistav disjunktsioon]]
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| [[es:Disyunción exclusiva]]
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| [[eo:Logika malinkluziva aŭo]]
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| [[fa:یای مانعةالجمع]]
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| [[fr:Fonction OU exclusif]]
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| [[ko:배타적 논리합]]
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| [[it:Disgiunzione esclusiva]]
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| [[he:או מוציא]]
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| [[mk:Исклучителна дисјункција]]
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| [[nl:Exclusieve disjunctie]]
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| [[ja:排他的論理和]]
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| [[no:Eksklusiv disjunksjon]]
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| [[pms:Disgionsion esclusiva]]
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| [[pl:Alternatywa wykluczająca]]
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| [[pt:Disjunção exclusiva]]
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| [[ro:Disjuncție exclusivă]]
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| [[ru:Сложение по модулю 2]]
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| [[simple:Exclusive disjunction]]
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| [[sk:Vylučujúce alebo]]
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| [[tr:XOR kapısı]]
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| [[uk:Виключна диз'юнкція]]
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| [[zh:逻辑异或]]
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