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In algebraic equations, the value of one variable is often dependent on the value of another. For example, in the equation below, y is the \"dependent variable\" because its value is based on the value assigned to the \"independent variable\" x.","url":"https://techterms.com/definition/variable"} </script> </head> <body> <div id="full"> <header id="siteheader"> <div class="content"> <a href="#main" class="visuallyhidden">Skip to main content</a> <a href="/" class="logo"><img src="/svg/logo.svg" width="212" height="24" alt="TechTerms.com"></a> <div class="siteheader-middle"> <div class="searchwrapper collapsed"> <form id="search" class="search" action="/search" method="post"> <div class='autocomplete' role='combobox' aria-expanded='false' aria-owns='autocomplete-results'> <input type="text" id="term" name="term" placeholder="Search (e.g. variable, 5G, ISP, USB-C)" aria-label="Search (e.g. psd, docx, exe, jpg, zip)" autocomplete="off" class='autocomplete-input term' aria-autocomplete='both' aria-controls='autocomplete-results'> <button id="searchsubmit" class="searchsubmit"></button> </div> <ul id='autocomplete-results' class='autocomplete-results hidden' aria-label='Search'> </ul> </form> </div> <a href="/random" class="headerbutton random" id="random"><img src="/svg/random.svg" alt="random" width="16" height="16"></a> <button id="searchtoggle"><img src="/svg/search-white.svg" alt="search" width="18" height="18"></button> </div> <div class="siteheader-right"> <button id="menuopen"><img src="/svg/menu.svg" alt="open menu" width="18" height="16"></button> <nav id="sitemenu" class="collapsed"> <button id="menuclose"><img src="/svg/close.svg" alt="close menu" width="14" height="14"></button> <ul> <li><a href="/browse/">Terms</a></li> <li><a href="/quiz/">Quizzes</a></li> <li><a href="/help/">Help Center</a></li> <li class="mobile"><a href="/random">Random Term</a></li> <li class="settings"><button id="settings"><img src="/svg/settings.svg" alt="settings" width="22" height="22"></button> <div class="settingsmenu"> <fieldset> <legend>Theme</legend> <input id="theme-default" value="default" type="radio" name="theme" checked> <label for="theme-default">Light</label> <input id="theme-dark" value="dark" type="radio" name="theme" > <label for="theme-dark">Dark</label> <input id="theme-hc" value="hc" type="radio" name="theme" > <label for="theme-hc">High Contrast</label> </fieldset> <div class="fontsizewrapper"><label for="fontsize">Font Size<input type="range" id="fontsize" name="fontsize" min="14" max="26" step="2" value="20"></label><span class="currentsize">20</span></div> <button id="resetsettings">Reset</button> </div> </li> </ul> </nav> </div> </div> </header> <main> <div class="adTopLB"> <div id='div-gpt-ad-1589388248615-0'> </div> </div> <div id="main" class="def"> <div id="left"> <div class="card hasheader"> <div class="cardheader"> <div class="breadcrumbs"><a href="/">Home</a><svg viewBox="0 0 9 14" xmlns="http://www.w3.org/2000/svg"><path d="m0 14 9-7-9-7z"/></svg><a href="/category/technical">Technical Terms</a><svg viewBox="0 0 9 14" xmlns="http://www.w3.org/2000/svg"><path d="m0 14 9-7-9-7z"/></svg>Variable Definition</div> </div> <article> <h1>Variable</h1> <div class="adDefRect"> <div id='div-gpt-ad-1589302365809-0'> </div> </div> <p>In mathematics, a variable is a symbol or letter, such as "x" or "y," that represents a value. In algebraic equations, the value of one variable is often dependent on the value of another. For example, in the equation below, <span class="command">y</span> is the "dependent variable" because its value is based on the value assigned to the "independent variable" <span class="command">x</span>.</p> <p><span class="command">y = 10 + 2x</span></p> <p>The equation above may also be called a <a href="/definition/function">function</a> since y is a function of x. If x = 1, then y = 12. If x = 2, then y = 14.</p> <p>Variables are also used in computer programming to store specific values within a <a href="/definition/program">program</a>. They are assigned both a <a href="/definition/datatype">data type</a> as well as a value. For example, a variable of the <a href="/definition/string">string</a> data type may contain a value of "<span class="command">sample text</span>" while a variable of the <a href="/definition/integer">integer</a> data type may contain a value of "<span class="command">11</span>". Some <a href="/definition/programming_language">programming languages</a> require variables to be declared before they can be used, while others allow variables to be created on the fly. The data type, if not defined explicitly, is determined based on the initial value given to the variable.</p> <p>A function within a program may contain multiple variables, each of which may be assigned different values based on the <a href="/definition/input">input</a> parameters. Likewise, a variable may also be used to return a specific value as the <a href="/definition/output">output</a> of a function. In the <a href="/definition/java">Java</a> example below, the variable <span class="command">i</span> is incremented during each <a href="/definition/iteration">iteration</a> of the <span class="command">while</span> loop, and <span class="command">x</span> is returned as the output.</p> <p><span class="command">while (i < max)</span><br> <span class="command">{</span><br> <span class="command">  x = x+10;</span><br> <span class="command">  i++;</span><br> <span class="command">}</span><br> <span class="command">…</span><br> <span class="command">return x;</span></p> <p>As the name implies, the value of a variable can change. Variables that store values that do not change are called <a href="/definition/constant">constants</a>.</p> <div class="adBotLB"> <div id='div-gpt-ad-1589236206757-0'> </div> </div> <div class="cardfooter"> <div class="upDate"><div class="author">Updated <span class="pdate">May 3, 2012</span> by <a href="/authors/per_christensson">Per C.</a></div></div><div id="citations"> <div class="tabs"> <div role="tablist" aria-label="citations"> <button role="tab" aria-selected="false" aria-controls="apa" tabindex="-1">APA</button> <button role="tab" aria-selected="false" aria-controls="mla" tabindex="-1">MLA</button> <button role="tab" aria-selected="false" aria-controls="chicago" tabindex="-1">Chicago</button> <button role="tab" aria-selected="false" aria-controls="html" tabindex="-1">HTML</button> <button role="tab" aria-selected="false" aria-controls="link" tabindex="-1">Link</button> </div> <div class="citationwrap"> <div id="apa" role="tabpanel" class="citation" hidden> </div> <div id="mla" role="tabpanel" class="citation" hidden> </div> <div id="chicago" role="tabpanel" class="citation" hidden> </div> <div id="html" role="tabpanel" class="citation" hidden> </div> <div id="link" role="tabpanel" class="citation" hidden> <div>https://techterms.com/definition/variable</div> </div> <button id="citecopy"><span class="visuallyhidden">Copy</span><svg enable-background="new 0 0 488.3 488.3" viewBox="-7.5 -7.5 495.8 503.3" xmlns="http://www.w3.org/2000/svg"><path d="m314.25 85.4h-227c-21.3 0-38.6 17.3-38.6 38.6v325.7c0 21.3 17.3 38.6 38.6 38.6h227c21.3 0 38.6-17.3 38.6-38.6v-325.7c-.1-21.3-17.4-38.6-38.6-38.6zm11.5 364.2c0 6.4-5.2 11.6-11.6 11.6h-227c-6.4 0-11.6-5.2-11.6-11.6v-325.6c0-6.4 5.2-11.6 11.6-11.6h227c6.4 0 11.6 5.2 11.6 11.6z" stroke-width="15"/><path d="m401.05 0h-227c-21.3 0-38.6 17.3-38.6 38.6 0 7.5 6 13.5 13.5 13.5s13.5-6 13.5-13.5c0-6.4 5.2-11.6 11.6-11.6h227c6.4 0 11.6 5.2 11.6 11.6v325.7c0 6.4-5.2 11.6-11.6 11.6-7.5 0-13.5 6-13.5 13.5s6 13.5 13.5 13.5c21.3 0 38.6-17.3 38.6-38.6v-325.7c0-21.3-17.3-38.6-38.6-38.6z" stroke-width="15"/></svg></button> </div> </div> </div> </div> </article> </div> <div id="defquiz" class="card"> <h2 class="heading logoheading"><img src="/img/main/quiz.png" alt="quiz" style="width:45px">Test Your Knowledge</h2> <div class="quizBox"> <div class="quizBody"> <p class="quizQuestion">Which term is most similar to "logging on?"</p> <div class="quizTable"> <div id="ansButtonA" class="answerButton activeButton" data-answer="Anum" data-date="2020-03-09"><span class="ansLetter">A</span> <div class="answerCell"><span id="answerA" class="quizAnswer">Encrypting</span> <div class="answerBar"> <div id="quizBarA" class="quizBar"></div><span id="quizPercA" class="quizperc">0%</span> </div> </div> </div> <div id="ansButtonB" class="answerButton activeButton" data-answer="Bnum" data-date="2020-03-09"><span class="ansLetter">B</span> <div class="answerCell"><span id="answerB" class="quizAnswer">Authenticating</span> <div class="answerBar"> <div id="quizBarB" class="quizBar"></div><span id="quizPercB" class="quizperc">0%</span> </div> </div> </div> <div id="ansButtonC" class="answerButton activeButton" data-answer="Cnum" data-date="2020-03-09"><span class="ansLetter">C</span> <div class="answerCell"><span id="answerC" class="quizAnswer">Reformatting</span> <div class="answerBar"> <div id="quizBarC" class="quizBar"></div><span id="quizPercC" class="quizperc">0%</span> </div> </div> </div> <div id="ansButtonD" class="answerButton activeButton" data-answer="Dnum" data-date="2020-03-09"><span class="ansLetter">D</span> <div class="answerCell"><span id="answerD" class="quizAnswer">Reloading</span> <div class="answerBar"> <div id="quizBarD" class="quizBar"></div><span id="quizPercD" class="quizperc">0%</span> </div> </div> </div> <div class="quizResult"><div class="qmsg"> <b class="quizPass">Correct!</b> <b class="quizFail">Incorrect!</b>   <span class="customMessage"></span>  View the <a href="/definition/log_on">Log On definition</a>.</div> <a href="/quiz/#morequizzes" class="quizNext btnprimary">More Quizzes →</a> </div> </div> </div> </div> </div> </div> <div id="right"> <div class="prevnext"> <a href="vaporware"><span class="arrow">‹</span>  <span class="linktext">Vaporware</span></a><span> | </span><a href="vci"><span class="linktext">VCI</span>  <span class="arrow">›</span></a></div> <div class="tf card"> <h2 class="heading">Tech Factor</h2> <a href="/help/tech_factor" class="info" title="What is the Tech Factor?">?</a> <a href="/techfactor/3"><span class="factor">3</span><span class="denom"> / 10</span></a></div> <div class="adRightSky"> <div id='div-gpt-ad-1589233879778-0'> </div> </div> </div> <div class="techterms card"> <h2 class="heading">The Tech Terms Computer Dictionary</h2> <p>The definition of Variable on this page is an original definition written by the <a href="/authors/">TechTerms.com team</a>. If you would like to reference this page or cite this definition, please use the green citation links above.</p> <p>The goal of TechTerms.com is to explain computer terminology in a way that is easy to understand. We strive for simplicity and accuracy with every definition we publish. 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