<?xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>C on kenji.blog</title><link>http://kenji.blog/fr/tags/c/</link><description>Recent content in C on kenji.blog</description><generator>Hugo -- gohugo.io</generator><language>fr</language><copyright>kenjinote</copyright><lastBuildDate>Sat, 24 Aug 2024 09:38:10 +0900</lastBuildDate><atom:link href="http://kenji.blog/fr/tags/c/index.xml" rel="self" type="application/rss+xml"/><item><title>Code C pour générer des nombres premiers</title><link>http://kenji.blog/fr/p/code-c-pour-generer-des-nombres-premiers/</link><pubDate>Sat, 24 Aug 2024 09:38:10 +0900</pubDate><guid>http://kenji.blog/fr/p/code-c-pour-generer-des-nombres-premiers/</guid><description>&lt;img src="http://kenji.blog/p/%E7%B4%A0%E6%95%B0%E3%82%92%E7%94%9F%E6%88%90%E3%81%99%E3%82%8Bc%E8%A8%80%E8%AA%9E%E3%82%B3%E3%83%BC%E3%83%89/img.png" alt="Featured image of post Code C pour générer des nombres premiers" />&lt;p>Voici un code C simple qui génère des nombres premiers dans une plage spécifiée. Dans cet exemple, nous énumérons les nombres premiers de 1 à n.&lt;/p>
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&lt;pre tabindex="0" class="chroma">&lt;code class="language-cpp" data-lang="cpp">&lt;span class="line">&lt;span class="cl">&lt;span class="cp">#include&lt;/span> &lt;span class="cpf">&amp;lt;stdio.h&amp;gt;&lt;/span>&lt;span class="cp">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="cp">#include&lt;/span> &lt;span class="cpf">&amp;lt;stdbool.h&amp;gt;&lt;/span>&lt;span class="cp">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="cp">&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="kt">bool&lt;/span> &lt;span class="nf">isPrime&lt;/span>&lt;span class="p">(&lt;/span>&lt;span class="kt">int&lt;/span> &lt;span class="n">num&lt;/span>&lt;span class="p">)&lt;/span> &lt;span class="p">{&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="k">if&lt;/span> &lt;span class="p">(&lt;/span>&lt;span class="n">num&lt;/span> &lt;span class="o">&amp;lt;=&lt;/span> &lt;span class="mi">1&lt;/span>&lt;span class="p">)&lt;/span> &lt;span class="k">return&lt;/span> &lt;span class="nb">false&lt;/span>&lt;span class="p">;&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="k">if&lt;/span> &lt;span class="p">(&lt;/span>&lt;span class="n">num&lt;/span> &lt;span class="o">&amp;lt;=&lt;/span> &lt;span class="mi">3&lt;/span>&lt;span class="p">)&lt;/span> &lt;span class="k">return&lt;/span> &lt;span class="nb">true&lt;/span>&lt;span class="p">;&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="k">if&lt;/span> &lt;span class="p">(&lt;/span>&lt;span class="n">num&lt;/span> &lt;span class="o">%&lt;/span> &lt;span class="mi">2&lt;/span> &lt;span class="o">==&lt;/span> &lt;span class="mi">0&lt;/span> &lt;span class="o">||&lt;/span> &lt;span class="n">num&lt;/span> &lt;span class="o">%&lt;/span> &lt;span class="mi">3&lt;/span> &lt;span class="o">==&lt;/span> &lt;span class="mi">0&lt;/span>&lt;span class="p">)&lt;/span> &lt;span class="k">return&lt;/span> &lt;span class="nb">false&lt;/span>&lt;span class="p">;&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="k">for&lt;/span> &lt;span class="p">(&lt;/span>&lt;span class="kt">int&lt;/span> &lt;span class="n">i&lt;/span> &lt;span class="o">=&lt;/span> &lt;span class="mi">5&lt;/span>&lt;span class="p">;&lt;/span> &lt;span class="n">i&lt;/span> &lt;span class="o">*&lt;/span> &lt;span class="n">i&lt;/span> &lt;span class="o">&amp;lt;=&lt;/span> &lt;span class="n">num&lt;/span>&lt;span class="p">;&lt;/span> &lt;span class="n">i&lt;/span> &lt;span class="o">+=&lt;/span> &lt;span class="mi">6&lt;/span>&lt;span class="p">)&lt;/span> &lt;span class="p">{&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="k">if&lt;/span> &lt;span class="p">(&lt;/span>&lt;span class="n">num&lt;/span> &lt;span class="o">%&lt;/span> &lt;span class="n">i&lt;/span> &lt;span class="o">==&lt;/span> &lt;span class="mi">0&lt;/span> &lt;span class="o">||&lt;/span> &lt;span class="n">num&lt;/span> &lt;span class="o">%&lt;/span> &lt;span class="p">(&lt;/span>&lt;span class="n">i&lt;/span> &lt;span class="o">+&lt;/span> &lt;span class="mi">2&lt;/span>&lt;span class="p">)&lt;/span> &lt;span class="o">==&lt;/span> &lt;span class="mi">0&lt;/span>&lt;span class="p">)&lt;/span> &lt;span class="k">return&lt;/span> &lt;span class="nb">false&lt;/span>&lt;span class="p">;&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="p">}&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="k">return&lt;/span> &lt;span class="nb">true&lt;/span>&lt;span class="p">;&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="p">}&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="kt">void&lt;/span> &lt;span class="nf">printPrimes&lt;/span>&lt;span class="p">(&lt;/span>&lt;span class="kt">int&lt;/span> &lt;span class="n">n&lt;/span>&lt;span class="p">)&lt;/span> &lt;span class="p">{&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="n">printf&lt;/span>&lt;span class="p">(&lt;/span>&lt;span class="s">&amp;#34;2 &amp;#34;&lt;/span>&lt;span class="p">);&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="k">for&lt;/span> &lt;span class="p">(&lt;/span>&lt;span class="kt">int&lt;/span> &lt;span class="n">i&lt;/span> &lt;span class="o">=&lt;/span> &lt;span class="mi">3&lt;/span>&lt;span class="p">;&lt;/span> &lt;span class="n">i&lt;/span> &lt;span class="o">&amp;lt;=&lt;/span> &lt;span class="n">n&lt;/span>&lt;span class="p">;&lt;/span> &lt;span class="n">i&lt;/span> &lt;span class="o">+=&lt;/span> &lt;span class="mi">2&lt;/span>&lt;span class="p">)&lt;/span> &lt;span class="p">{&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="k">if&lt;/span> &lt;span class="p">(&lt;/span>&lt;span class="n">isPrime&lt;/span>&lt;span class="p">(&lt;/span>&lt;span class="n">i&lt;/span>&lt;span class="p">))&lt;/span> &lt;span class="p">{&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="n">printf&lt;/span>&lt;span class="p">(&lt;/span>&lt;span class="s">&amp;#34;%d &amp;#34;&lt;/span>&lt;span class="p">,&lt;/span> &lt;span class="n">i&lt;/span>&lt;span class="p">);&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="p">}&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="p">}&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="n">printf&lt;/span>&lt;span class="p">(&lt;/span>&lt;span class="s">&amp;#34;&lt;/span>&lt;span class="se">\n&lt;/span>&lt;span class="s">&amp;#34;&lt;/span>&lt;span class="p">);&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="p">}&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="kt">int&lt;/span> &lt;span class="nf">main&lt;/span>&lt;span class="p">()&lt;/span> &lt;span class="p">{&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="kt">int&lt;/span> &lt;span class="n">n&lt;/span>&lt;span class="p">;&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="n">printf&lt;/span>&lt;span class="p">(&lt;/span>&lt;span class="s">&amp;#34;Veuillez entrer la valeur maximale de la plage pour générer des nombres premiers : &amp;#34;&lt;/span>&lt;span class="p">);&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="n">scanf&lt;/span>&lt;span class="p">(&lt;/span>&lt;span class="s">&amp;#34;%d&amp;#34;&lt;/span>&lt;span class="p">,&lt;/span> &lt;span class="o">&amp;amp;&lt;/span>&lt;span class="n">n&lt;/span>&lt;span class="p">);&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="n">printf&lt;/span>&lt;span class="p">(&lt;/span>&lt;span class="s">&amp;#34;Les nombres premiers de 1 à %d sont les suivants :&lt;/span>&lt;span class="se">\n&lt;/span>&lt;span class="s">&amp;#34;&lt;/span>&lt;span class="p">,&lt;/span> &lt;span class="n">n&lt;/span>&lt;span class="p">);&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="n">printPrimes&lt;/span>&lt;span class="p">(&lt;/span>&lt;span class="n">n&lt;/span>&lt;span class="p">);&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl"> &lt;span class="k">return&lt;/span> &lt;span class="mi">0&lt;/span>&lt;span class="p">;&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="p">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/td>&lt;/tr>&lt;/table>
&lt;/div>
&lt;/div>&lt;p>Ce code fonctionne de la manière suivante :&lt;/p>
&lt;ol>
&lt;li>Fonction isPrime : Détermine si un nombre donné est premier. Par souci d&amp;rsquo;efficacité, on vérifie d&amp;rsquo;abord s&amp;rsquo;il est divisible par 2 et 3, puis on procède à la vérification par multiples de 6.&lt;/li>
&lt;li>Fonction printPrimes : Produit les nombres premiers dans une plage spécifiée. Le 2 est affiché en premier, puis seuls les nombres impairs sont vérifiés.&lt;/li>
&lt;li>Fonction main : Demande à l&amp;rsquo;utilisateur de saisir la valeur maximale de la plage et affiche les nombres premiers dans cette plage.&lt;/li>
&lt;/ol>
&lt;p>Si vous compilez et exécutez ce code, les nombres premiers dans la plage spécifiée seront affichés.&lt;/p></description></item></channel></rss>