http://coderwiki.org/index.php?action=history&feed=atom&title=EnumEnum - Revision history2026-05-19T01:41:25ZRevision history for this page on the wikiMediaWiki 1.44.0http://coderwiki.org/index.php?title=Enum&diff=107&oldid=prevDylan: new: info, example, other sum, other algebraic2025-08-15T09:04:13Z<p>new: info, example, other sum, other algebraic</p>
<p><b>New page</b></p><div>An '''enum''' is a [[sum type]] (a type of [[algebraic data type]]) in which its [[value]] represents one of a set number of possible states.<br />
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This makes [[Invalid state|invalid states]] unrepresentable, as the [[variable]] of the enum [[data type]] can '''only''' store certain [[Value|values]], nothing else.<br />
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== Example ==<br />
Say you are writing a program to track animals in a zoo.<br />
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You could have an '''enum''' type called <code>Animal</code> to store the different animals in the zoo. [[Variable|Variables]] of this [[Data type|type]] could then only contain one of four [[Value|values]]:<br />
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* Parrot<br />
* Monkey<br />
* Tiger<br />
* Giraffe<br />
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This has the benefit of making [[invalid state]] impossible: we are guaranteed that the value of an <code>Animal</code> [[variable]] will always be one of the 4 above.<br />
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== Other sum types ==<br />
See: [[Sum type]]<br />
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== Other algebraic data types ==<br />
See: [[Algebraic data type]]</div>Dylan