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Iterative functions run the same code block repeatedly and automatically, processing multiple chunks of <a href="/definition/data">data</a> in sequence without redundant code.</p> <p>The most common forms of iteration used in computer <a href="/definition/program">programs</a> are <b>while loops</b> and <b>for loops</b>. <a href="/definition/loop">Loops</a> run repeatedly as long as a specified condition is true. For example, a <a href="/definition/developer">developer</a> first creates a <a href="/definition/variable">variable</a> that tracks how many times the function has run, then sets a total number of loops. After each iteration finishes, it increments the tracking variable and runs again until the tracking variable reaches the total number previously set. </p> <p>While the specific <a href="/definition/syntax">syntax</a> of <b>while</b> and <b>for</b> loops varies in each <a href="/definition/programming_language">programming language</a>, they often follow a similar pattern. The syntax for these loops in <a href="/definition/java">Java</a> looks like this:</p> <p><b>While loop:</b> <span class="command">while (i < 30) { ... i++; }</span></p> <p><b>For loop:</b> <span class="command">for (i=0; i < 30; i++) { ... }</span></p> <p>Both samples first create a tracking variable, <span class="command">i</span>, and a total number of times for the iteration to run. The <b>while</b> loop includes the incrementation command, <span class="command">i++</span>, at the end of the function, then checks the condition again when it starts over. The <b>for</b> loop creates the tracking variable, the total number of iterations, and how to increment the tracking variable at the start.</p> <figure class="deffig"> <img src="https://techterms.com/img/xl/iteration_713.png" alt="An while loop repeats as long as its condition is true, and ends once its condition is false" width="600" height="140" class="defimg"> <figcaption class="caption">An while loop repeats as long as its condition is true, and ends once its condition is false</figcaption> </figure> <p>Software developers use iterative loops for many common purposes. For example, a developer may use an iterative function to perform calculations on each value in an <a href="/definition/array">array</a>, running once for each array address until it reaches the end. A <a href="/definition/web_development">web developer</a> may use a <a href="/definition/php">PHP</a> script with an iterative loop to pull lines from a database <a href="/definition/record">record</a>, add <a href="/definition/html">HTML</a> formatting to display that content in a table, then close the table after getting the final line in the <a href="/definition/database">database</a> record.</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">June 5, 2023</span> by <a href="/authors/brian_pickle">Brian P.</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" 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10</span></a></div> <div class="listBox card related"> <h2 class="heading">Related Terms</h2> <div class="rlists"> <ol> <li><a href="/definition/computer_science">Computer Science</a></li> <li><a href="/definition/function">Function</a></li> <li><a href="/definition/recursion">Recursion</a></li> <li><a href="/definition/programming_language">Programming Language</a></li> </ol> <ol start="5"><li><a href="/definition/recursive_function">Recursive Function</a></li> <li><a href="/definition/variable">Variable</a></li> <li><a href="/definition/loop">Loop</a></li> <li><a href="/definition/program">Program</a></li> </ol> </div> </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 Iteration on this page is an original definition written by the <a href="/authors/">TechTerms.com team</a>. 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