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<!DOCTYPE html> <html lang="en"> <head> <title>classes from FOLDOC</title> <meta http-equiv="Content-Security-Policy" content="default-src 'unsafe-inline' http: https:"> <meta name="verify-v1" content="siAI0ZOMn41hao0E/T76D1I2L3MtFjzE48P3ctCjRNU="> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <meta name="msapplication-TileColor" content="#da532c"> <meta name="theme-color" content="#ffffff"> <meta name="google-translate-customization" content="828219db36930e1e-c51d915bf2ea717c-g9b503f9a85d5b5a7-a">  <script src="https://www.googletagmanager.com/gtag/js?id=UA-9715943-1"></script> <script> window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', 'UA-9715943-1'); </script>  <link href="//fonts.googleapis.com/css?family=Duru+Sans%7CBelgrano%7CInconsolata%7CAlef%7CArmata" rel="stylesheet" type="text/css"> <link rel="stylesheet" type="text/css" href="/css/layout.css?2">  <link rel="apple-touch-icon" sizes="152x152" href="/im/apple-touch-icon.png"> <link rel="icon" type="image/png" sizes="32x32" href="/im/favicon-32x32.png"> <link rel="icon" type="image/png" sizes="16x16" href="/im/favicon-16x16.png"> <link rel="manifest" href="/im/site.webmanifest"> <link rel="mask-icon" href="/im/safari-pinned-tab.svg" color="#5bbad5"> <link rel="canonical" href="https://foldoc.org/classes"> <link rel="alternate" type="application/rss+xml" title="FOLDOC" href="/rss.xml"> <link rel="search" title="FOLDOC" type="application/opensearchdescription+xml" href="//foldoc.org/search.xml">  <script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js?client=ca-pub-5521724329338202" crossorigin="anonymous"></script>  </head> <body> <div id="fb-root"></div> <script> (function (d, s, id) { var js, fjs = d.getElementsByTagName(s)[0]; if (d.getElementById(id)) return; js = d.createElement(s); js.id = id; js.src = "//connect.facebook.net/en_GB/all.js#xfbml=1"; fjs.parentNode.insertBefore(js, fjs); }(document, 'script', 'facebook-jssdk')); </script> <div id="container"> <div id="left"> <a href="/"> <img src="/foldoc.gif" width="300" height="98" alt="Free On-line Dictionary of Computing" class="logo"> </a> <div id="nav"> <a href="/contents.html" class="button">Contents</a> <a href="/help.html" class="button">Help</a> <a href="/random-entry" class="button">Random</a> </div> <form action="/"> <input type="text" name="query" id="query" autofocus="autofocus"> <input type="submit" name="action" value="Search" class="button"> </form> <div id="content"> <h2>CLASP</h2> <p></p> <a href="/Computer+Language+for+AeronauticS+and+Programming">Computer Language for AeronauticS and Programming</a> <p></p> <h2>class</h2> <p></p> <p><<i><a href="contents/programming.html">programming</a></i>></p> <p> 1. The prototype for an <a href="/object">object</a> in an <a href="/object-oriented+language">object-oriented language</a>; analogous to a <a href="/derived+type">derived type</a> in a <a href="/procedural+language">procedural language</a>. A class may also be considered to be a set of objects which share a common structure and behaviour. The structure of a class is determined by the <a href="/class+variables">class variables</a> which represent the <a href="/state">state</a> of an object of that class and the behaviour is given by a set of <a href="/methods">methods</a> associated with the class. <p></p> Classes are related in a <a href="/class+hierarchy">class hierarchy</a>. One class may be a specialisation (a "<a href="/subclass">subclass</a>") of another (one of its "<a href="/superclasses">superclasses</a>") or it may be composed of other classes or it may use other classes in a <a href="/client-server">client-server</a> relationship. A class may be an <a href="/abstract+class">abstract class</a> or a <a href="/concrete+class">concrete class</a>. <p></p> See also <a href="/signature">signature</a>. <p></p> <p><<i><a href="contents/programming.html">programming</a></i>></p> <p> 2. See <a href="/type+class">type class</a>. <p></p> <p><<i><a href="contents/networking.html">networking</a></i>></p> <p> 3. One of three types of <a href="/Internet+addresses">Internet addresses</a> distinguished by their most significant bits. <p></p> <p><<i><a href="contents/language.html">language</a></i>></p> <p> 3. A language developed by the <a href="/Andrew+Project">Andrew Project</a>. It was one of the first attempts to add <a href="/object-oriented">object-oriented</a> features to <a href="/C">C</a>. <p></p> <p class="updated">Last updated: <a href="/new.html">1995-05-01</a></p> <p></p> <h2>Class 5 switch</h2> <p></p> <p><<i><a href="contents/communications.html">communications</a></i>></p> <p> The lowest designation used in <a href="/AT%26T">AT&T</a>'s hierarchical <a href="/General+Toll+Switching+Plan">General Toll Switching Plan</a>, developed in 1929. <p></p> <p class="updated">Last updated: <a href="/new.html">2013-09-14</a></p> <p></p> <h2>class hierarchy</h2> <p></p> <p><<i><a href="contents/programming.html">programming</a></i>></p> <p> In <a href="/object-oriented+programming">object-oriented programming</a>, a set of <a href="/classes">classes</a> related by <a href="/inheritance">inheritance</a>. Each class is a "subclass" of another class - its "superclass". The subclass contains all the features of its superclass, but may add new features or redefine existing features. The features of a class are the set of <a href="/attributes">attributes</a> (or "properties") that an object of that class has and the <a href="/methods">methods</a> that can be invoked on it. <p></p> If each class has a just one superclass, this is called <a href="/single+inheritance">single inheritance</a>. The opposite is <a href="/multiple+inheritance">multiple inheritance</a>, under which a class may have multiple superclasses. Single inheritance gives the class hierarchy a <a href="/tree">tree</a> structure whereas multiple inheritance gives a <a href="/directed+graph">directed graph</a>. Typically there is one class at the top of the hierarchy which is the "object" class, the most general class that is an ancestor of all others and which has no superclass. <p></p> In computing, as in genealogy, trees grow downwards, which is why subclasses are considered to be "below" their superclasses. <p></p> When <a href="/invoking+a+method">invoking a method</a> on an <a href="/object">object</a>, the method is first looked for in the object's class, then the superclass of that class, and so on up the hierarchy until it is found. Thus a class need only define those methods which are specific to it and it will inherit all other methods from all its superclasses. An object of the subclass can do everything that an object of the superclass can and possible more. <p></p> <a href="/C%2b%2b">C++</a> calls the superclass the "base class" and the subclass the "derived class" (not to be confused with a <a href="/derived+type">derived type</a>). <p></p> <p class="updated">Last updated: <a href="/new.html">2014-09-06</a></p> <p></p> <h2>classic</h2> <p></p> <p><<i><a href="contents/jargon.html">jargon</a></i>></p> <p> An adjective used before or after a noun to describe the original version of something, especially if the original is considered to be better. <p></p> Examples include "Star Trek Classic" - the original TV series as opposed to the films, ST The Next Generation or any of the other spin-offs and follow-ups; or "PC Classic" - <a href="/IBM">IBM</a>'s <a href="/ISA">ISA</a>-bus computers as opposed to the <a href="/PS/2">PS/2</a> series. <p></p> <p class="updated">Last updated: <a href="/new.html">1996-10-27</a></p> <p></p> <h2>Classic-Ada</h2> <p></p> <p><<i><a href="contents/language.html">language</a></i>></p> <p> An <a href="/object-oriented">object-oriented</a> extension to <a href="/Ada">Ada</a>, said to be like <a href="/Smalltalk">Smalltalk</a>. It is implemented as an <a href="/Ada">Ada</a> <a href="/preprocessor">preprocessor</a>. <p></p> <p class="updated">Last updated: <a href="/new.html">1994-12-05</a></p> <p></p> <h2>classical logic</h2> <p></p> <p><<i><a href="contents/logic.html">logic</a></i>></p> <p> Non-<a href="/intuitionistic+logic">intuitionistic logic</a>. <p></p> <p class="updated">Last updated: <a href="/new.html">1995-04-13</a></p> <p></p> <h2>Classic C</h2> <p></p> <a href="/K%26R+C">K&R C</a> <p></p> <h2>Classless Inter-Domain Routing</h2> <p></p> <p><<i><a href="contents/networking.html">networking</a></i>></p> <p> (CIDR) /sid*r/ A technique that summarises a block of <a href="/Internet+addresses">Internet addresses</a> in a <a href="/routing+table">routing table</a> as an address in <a href="/dotted+decimal+notation">dotted decimal notation</a> followed by a <a href="/forward+slash">forward slash</a> and a two-digit decimal number giving the number of leading one bits in the subnet mask. For example, 123.123.123.0/24 specifies a subnet mask of 11111111.11111111.11111111.00000000 (binary), implying the block of addresses 123.123.123.0 through 123.123.123.255. <p></p> CIDR is "classless" because it is not limited to the subnet masks specified by <a href="/Internet+address">Internet address</a> classes A, B and C. <p></p> According to <a href="/RFC+1519">RFC 1519</a>, CIDR was implemented to distribute Internet address space more efficiently and to provide a mechanism for <a href="/IP+route+aggregation">IP route aggregation</a>. This in turn reduces the number of entries in IP routing tables, enabling faster, more efficient routing, e.g. using <a href="/routing">routing</a> <a href="/protocols">protocols</a> such as <a href="/OSPF">OSPF</a>. CIDR is supported by <a href="/BGP4">BGP4</a>. <p></p> See also <a href="/RFC+1467">RFC 1467</a>, <a href="/RFC+1518">RFC 1518</a>, <a href="/RFC+1520">RFC 1520</a>. <p></p> <p class="updated">Last updated: <a href="/new.html">2006-01-26</a></p> <p></p> <h2>class library</h2> <p></p> <p><<i><a href="contents/programming.html">programming</a></i>></p> <p> A <a href="/library">library</a> of reusable <a href="/class">class</a>es for use with an <a href="/object-oriented+programming">object-oriented programming</a> system. <p></p> <p class="updated">Last updated: <a href="/new.html">1994-12-05</a></p> <p></p> <h2>class method</h2> <p></p> <p><<i><a href="contents/programming.html">programming</a></i>></p> <p> 1. A <a href="/method">method</a> that operates on a <a href="/class+object">class object</a> (an <a href="/object">object</a> of <a href="/class">class</a> "class"). A class method is really just an ordinary <a href="/object+method">object method</a> that happens to operate on class objects. <p></p> A class method might, for example, return a list of objects representing the methods and attributes of the given class. <p></p> 2. A <a href="/static+method">static method</a>. <p></p> <p class="updated">Last updated: <a href="/new.html">2014-09-06</a></p> <p></p> <h2>class object</h2> <p></p> <p><<i><a href="contents/programming.html">programming</a></i>></p> <p> In <a href="/object-oriented+programming">object-oriented programming</a>, an <a href="/object">object</a> of <a href="/class">class</a> "class" that represents a <a href="/class">class</a> at <a href="/run+time">run time</a>. The existence of class objects allows <a href="/introspection">introspection</a> - the ability for a program to discover and modify attributes of its own code. (See <a href="/self-modifying+code">self-modifying code</a>). <p></p> A class object may also be used for "housekeeping" tasks like keeping count of how many objects of the class have been created, though this may also be done by some kind of <a href="/collection">collection</a> object. <p></p> A <a href="/class+method">class method</a> is a <a href="/method">method</a> that operates on class objects. <p></p> <p class="updated">Last updated: <a href="/new.html">2014-09-06</a></p> <p></p> <h2>Class Oriented Ring Associated Language</h2> <p></p> <p><<i><a href="contents/language.html">language</a></i>></p> <p> (CORAL) A language developed by L.G. Roberts at <a href="/MIT">MIT</a> in 1964 for graphical display and systems programming on the <a href="/TX-2">TX-2</a>. It used "rings" (circular lists) from <a href="/Sketchpad">Sketchpad</a>. <p></p> ["Graphical Communication and Control Languages", L.B. Roberts, Information System Sciences: Proc Second Congress, 1965]. <p></p> [Sammet 1969, p.462]. <p></p> <p class="updated">Last updated: <a href="/new.html">1994-11-30</a></p> <p></p> <h2>Class-Relation Method</h2> <p></p> <p><<i><a href="contents/programming.html">programming</a></i>></p> <p> A design technique based on the concepts of <a href="/object-oriented+programming">object-oriented programming</a> and the <a href="/Entity-Relationship+model">Entity-Relationship model</a> from the French company <a href="/Softeam">Softeam</a>. <p></p> <p class="updated">Last updated: <a href="/new.html">1994-12-05</a></p> <p></p> <p class="vertical-space"></p><h3>Nearby terms:</h3> <p class="neighbours"> <a href="/Clarify">Clarify</a> &diams; <a href="/Clarion">Clarion</a> &diams; <a href="/Claris">Claris</a> &diams; <b><a href="/CLASP">CLASP</a></b> &diams; <a href="/class">class</a> &diams; <a href="/Class+5+switch">Class 5 switch</a> &diams; <a href="/class+hierarchy">class hierarchy</a> </p> <p> Try this search on <a href="https://www.wikipedia.org/wiki/Special:Search?search=classes">Wikipedia</a>, <a href="https://www.wiktionary.org/wiki/classes">Wiktionary</a>, <a href="https://www.google.com/search?q=define:classes">Google</a>, <a href="https://www.onelook.com/?w=classes">OneLook</a>. </p> <p class="vertical-space"></p> <hr> <div></div> <hr>  <div id="HCB_comment_box">Loading</div> <link rel="stylesheet" type="text/css" href="//www.htmlcommentbox.com/static/skins/bootstrap/twitter-bootstrap.css?v=0"> <script language="javascript" id="hcb"> hcb_user = { PAGE: 'https://foldoc.org/classes', comments_header: ' ', no_comments_msg: ' ', err_comment_empty: 'Your comment was not posted because it was empty!', rss: '', }; var s = document.createElement("script"); s.setAttribute("type", "text/javascript"); s.setAttribute("src", "//www.htmlcommentbox.com/jread?page=" + escape(hcb_user.PAGE).replace(/\+/g, "%2B") + "&mod=%241%24wq1rdBcg%24.0y2uzvjA2bsnhzpXVq9F." + "&opts=17374&num=10"); // No e-mail field: 16846 if (typeof s != "undefined") document.getElementsByTagName("head")[0].appendChild(s); </script> <script> setTimeout(function () { document.getElementById('hcb_form_content').rows = 1 }, 1000); </script> <hr>  </div>  </div>  <div id="right"> <div id="google_translate_element"> <script> function googleTranslateElementInit() { new google.translate.TranslateElement({ pageLanguage: 'en' }, 'google_translate_element'); } </script> <script src="https://translate.google.com/translate_a/element.js?cb=googleTranslateElementInit"></script> </div> <p><br></p> <hr> <div id="social"> <div class="fb-like" data-href="http://foldoc.org/" data-layout="button_count" data-action="like" data-show-faces="false" data-share="true"> </div> <a href="https://twitter.com/share" class="twitter-share-button" data-via="foldoc"> Tweet </a> <script> if (!document.getElementById('twitter-wjs')) { var fjs = document.getElementsByTagName('script')[0], js = document.createElement('script'); js.id = 'twitter-wjs'; js.src = 'https://platform.twitter.com/widgets.js'; fjs.parentNode.insertBefore(js, fjs); } </script> </div> <hr> <div> <p></p> </div> <p> <a href="/rss.xml"> <img src="/orangerss.gif" width="14" height="14" alt="RSS feed of new items"> </a>   <a href="/new.html">Recent Updates</a>     |     <a href="/missing.html">Missing Terms</a> </p> <p>Updated: Sat, 05 Apr 2025 21:25:49 GMT</p> <p>15282 entries</p> <p><em><a href="/Free+On-line+Dictionary">Copyright Denis Howe 1985</a></em></p> </div>  </div>   <script type="text/javascript"> window._qevents = window._qevents || []; (function() { var elem = document.createElement('script'); elem.src = 'https://secure.quantserve.com/quant.js'; elem.async = true; elem.type = 'text/javascript'; var scpt = document.getElementsByTagName('script')[0]; scpt.parentNode.insertBefore(elem, scpt); })(); window._qevents.push({ qacct: 'p-48Rosdvs3EiOc', uid: '__INSERT_EMAIL_HERE__' }); </script> <noscript> <div style="display:none;"> <img src="https//pixel.quantserve.com/pixel/p-48Rosdvs3EiOc.gif" border="0" height="1" width="1" alt="Quantcast"/> </div> </noscript>  </body> </html>