{"id":862,"date":"2020-10-09T10:23:58","date_gmt":"2020-10-09T08:23:58","guid":{"rendered":"http:\/\/mathquiz.fr\/?page_id=862"},"modified":"2025-05-07T09:11:40","modified_gmt":"2025-05-07T07:11:40","slug":"structures-de-controle-les-boucles","status":"publish","type":"page","link":"https:\/\/mathquiz.fr\/?page_id=862","title":{"rendered":"Structures de contr\u00f4le : les boucles"},"content":{"rendered":"\n<hr class=\"wp-block-separator\"\/>\n\n\n\n<p>Afin de suivi le cours\/TD plus agr\u00e9able, je vous conseille de lire le guide vid\u00e9o disponible en cliquant sur l&rsquo;image ci-dessous. Vous pouvez par ailleurs optimiser votre espace de travail en ouvrant une fen\u00eatre consacr\u00e9 au guide vid\u00e9o et une autre \u00e0 la lecture de cette page web.<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><a href=\"https:\/\/youtu.be\/6yxYffZ_wiw\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" width=\"640\" height=\"446\" src=\"http:\/\/mathquiz.fr\/wp-content\/uploads\/2020\/11\/log.png\" alt=\"\" class=\"wp-image-1197\" srcset=\"https:\/\/mathquiz.fr\/wp-content\/uploads\/2020\/11\/log.png 640w, https:\/\/mathquiz.fr\/wp-content\/uploads\/2020\/11\/log-300x209.png 300w, https:\/\/mathquiz.fr\/wp-content\/uploads\/2020\/11\/log-370x258.png 370w\" sizes=\"(max-width: 640px) 100vw, 640px\" \/><\/a><\/figure><\/div>\n\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n\n<p>Afin de r\u00e9p\u00e9ter une instruction plusieurs fois, on utilise la structure de boucle. Imaginons un robot sur une chaine de production, qui r\u00e9p\u00e8te le m\u00eame mouvement. Sans structure de boucle, le programmeur serait oblig\u00e9 d&rsquo;\u00e9crire plusieurs fois les m\u00eames d&rsquo;instructions. C&rsquo;est une solution tr\u00e8s chronophage, surtout si le nombre r\u00e9p\u00e9tition \u00e9volue.<\/p>\n\n\n\n<p>La structure de boucle r\u00e9pond \u00e0 cette probl\u00e9matique. Elle est similaire \u00e0 la structure des conditions.<\/p>\n\n\n\n<p><strong><span class=\"has-inline-color has-vivid-red-color\">1. La boucle while (tant que) <\/span><\/strong><\/p>\n\n\n\n<p>Pour comprendre la structure de boucles, partons de plusieurs exemples :<\/p>\n\n\n<iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/Bte\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/Bte\">create.withcode.uk<\/a><\/iframe>\n\n\n\n<p><strong>Exemple 1 :<\/strong><\/p>\n\n\n\n<ul><li>L\u2019instruction 1&nbsp;: Affiche la chaine de caract\u00e8res \u00ab&nbsp;PUNITION &#8211; copier 1000 fois : Je cesserai insens\u00e9ment mes sottises insens\u00e9es en cours de SNT&nbsp;\u00bb.<\/li><li>L\u2019instruction 2&nbsp;: On stocke la valeur 1 dans une variable i.<\/li><li>L\u2019instruction 3&nbsp;: C\u2019est la structure de boucle while. Compos\u00e9es :<ul><li>De l\u2019instruction while qui marque le commencement de la boucle. Que l\u2019on peut traduire par Tant que<\/li><li>i&lt;=1000 est l\u2019assertion de la structure de boucle. Tant qu\u2019elle est vraie, on r\u00e9p\u00e8te les instructions du bloc d\u2019instructions de la boucle.<\/li><li>&nbsp;: permet de marquer la fin de l\u2019assertion.<\/li><\/ul><\/li><li>L\u2019instruction 4&nbsp;: affiche la chaine de caract\u00e8re \u00ab&nbsp;Ligne n&nbsp;\u00bb Valeur de la variable i&nbsp;\u00ab&nbsp;Je cesserai insens\u00e9ment mes sottises ensemenc\u00e9es en cours de SNT&nbsp;\u00bb<\/li><li>L\u2019instruction 5&nbsp;: Stocke dans la variable i la valeur de la variable i plus 1.<\/li><\/ul>\n\n\n\n<p><strong>Exemple 2 :<\/strong><\/p>\n\n\n<iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/Btf\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/Btf\">create.withcode.uk<\/a><\/iframe>\n\n\n\n<p>Tant que l\u2019assertion reponse==1 est vraie, les instructions des lignes 5 et 6 seront ex\u00e9cut\u00e9es.<\/p>\n\n\n\n<p><strong>Remarque :<\/strong> Comme pour les conditions, le bloc d&rsquo;instructions des boucles est indent\u00e9.<\/p>\n\n\n\n<p><strong>Exemple de boucle infini :<\/strong><\/p>\n\n\n<iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/Btg\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/Btg\">create.withcode.uk<\/a><\/iframe>\n\n\n\n<p>Si l\u2019on saisit la valeur 1 pour l\u2019instruction 2, l\u2019assertion reponse==1 sera vraie. Dans la structure de boucle, la valeur de la variable r\u00e9ponse n\u2019\u00e9volue plus. Par cons\u00e9quent, l\u2019assertion reponse==1 sera tout le temps vraie. L\u2019instruction 4 sera donc ex\u00e9cut\u00e9e \u00e0 l\u2019infinie. On dit que la boucle est une boucle infinie.<\/p>\n\n\n\n<p>Pour rappels, vous trouverez ci-dessous la liste des op\u00e9rateurs logiques :<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><strong>Op\u00e9rateur logique<\/strong><\/td><td><strong>R\u00f4le<\/strong><\/td><td><strong>Exemple<\/strong><\/td><\/tr><tr><td>==<\/td><td>Test de l\u2019\u00e9galit\u00e9<\/td><td>3==4&nbsp;: renvoi faux<\/td><\/tr><tr><td>!=<\/td><td>Test de diff\u00e9rence<\/td><td>3&nbsp;!=4&nbsp;: renvoi vrai<\/td><\/tr><tr><td>&lt;<\/td><td>Test inf\u00e9rieur<\/td><td>3&lt;4&nbsp;: renvoi vrai<\/td><\/tr><tr><td>&lt;=<\/td><td>Test inf\u00e9rieur ou \u00e9gal<\/td><td>4&lt;=3&nbsp;: renvoi faux<\/td><\/tr><tr><td>&gt;<\/td><td>Test sup\u00e9rieur<\/td><td>3&gt;4&nbsp;: renvoi faux<\/td><\/tr><tr><td>&gt;=<\/td><td>Test sup\u00e9rieur ou \u00e9gal<\/td><td>4&gt;=3&nbsp;: renvoi vrai<\/td><\/tr><tr><td>and<\/td><td>Et logique<\/td><td><\/td><\/tr><tr><td>or<\/td><td>Ou logique<\/td><td><\/td><\/tr><tr><td>not<\/td><td>Non logique<\/td><td><br><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n\n<p><strong><em>Exercice 1<\/em><\/strong><\/p>\n\n\n\n<p><strong>Tester le programme ci-dessous et expliquer l\u2019int\u00e9r\u00eat de l&rsquo;usage de la boucle.<\/strong><\/p>\n\n\n<iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/Bth\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/Bth\">create.withcode.uk<\/a><\/iframe>\n\n\n\n<div class=\"su-spoiler su-spoiler-style-default su-spoiler-icon-plus su-spoiler-closed\" data-scroll-offset=\"0\" data-anchor-in-url=\"no\"><div class=\"su-spoiler-title\" tabindex=\"0\" role=\"button\"><span class=\"su-spoiler-icon\"><\/span>Cliquer sur le + pour obtenir la r\u00e9ponse :<\/div><div class=\"su-spoiler-content su-u-clearfix su-u-trim\">R\u00e9ponse en vid\u00e9o <\/p>\n\n\n\n<figure class=\"wp-block-embed-youtube wp-block-embed is-type-rich is-provider-prise-en-charge-des-contenus-embarques wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe title=\"Les boucles - ex 1\" width=\"1040\" height=\"585\" src=\"https:\/\/www.youtube.com\/embed\/CoTeAXYT9z4?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<\/div><\/div>\n\n\n\n<p><strong><em>Exercice 2<\/em><\/strong><\/p>\n\n\n\n<p><strong>\u00c9crire un programme qui affiche le message suivant tant que la valeur 29 n\u2019est pas saisie : \u201dVeuillez saisir 29\u201d<\/strong><\/p>\n\n\n<iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/5\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/5\">create.withcode.uk<\/a><\/iframe>\n\n\n<div class=\"su-spoiler su-spoiler-style-default su-spoiler-icon-plus su-spoiler-closed\" data-scroll-offset=\"0\" data-anchor-in-url=\"no\"><div class=\"su-spoiler-title\" tabindex=\"0\" role=\"button\"><span class=\"su-spoiler-icon\"><\/span>Cliquer sur le + pour obtenir la r\u00e9ponse :<\/div><div class=\"su-spoiler-content su-u-clearfix su-u-trim\"><iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/Bti\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/Bti\">create.withcode.uk<\/a><\/iframe><\/div><\/div>\n\n\n\n<p><strong><span class=\"has-inline-color has-vivid-red-color\">2. La boucle for (pour)<\/span><\/strong><\/p>\n\n\n\n<p>Voici un type de boucle diff\u00e9rent. Ce type de boucle de sert qu\u2019\u00e0 r\u00e9p\u00e9ter un bloc d\u2019instructions un certain nombre de fois.<\/p>\n\n\n\n<p>Voici un exemple qui ex\u00e9cute exactement les m\u00eames instructions que dans l\u2019exemple 1.<\/p>\n\n\n<iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/Btj\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/Btj\">create.withcode.uk<\/a><\/iframe>\n\n\n\n<ul><li>La structure de boucle for de d\u00e9compose de la fa\u00e7on suivante\u00a0:<ul><li>for introduit la structure de la boucle de type pour.<\/li><li>i est la variable \u00e9voluant dans la boucle.<\/li><li>in range(0,1000) implique que la variable i va prendre les valeurs \u00e9voluant de 0 \u00e0 999 inclus. En tout 1000 instructions sont ex\u00e9cut\u00e9es.<\/li><li>\u00a0: permet de la structure de boucle.<\/li><\/ul><\/li><\/ul>\n\n\n\n<p><strong>Remarque&nbsp;:<\/strong> La boucle for est une boucle while&nbsp;\u00ab&nbsp;masqu\u00e9e&nbsp;\u00bb<\/p>\n\n\n\n<p>Si l&rsquo;on veut commenc\u00e9 par la ligne 1 et finir \u00e0 la ligne, il suffit d&rsquo;incr\u00e9menter de 1 les valeurs prises par la variable i.<\/p>\n\n\n<iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/Btk\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/Btk\">create.withcode.uk<\/a><\/iframe>\n\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n\n<p><strong><em>Exercice 3<\/em><\/strong><\/p>\n\n\n\n<p><strong>\u00c9crire un programme qui affiche \u201ccoucou\u201d 300 fois.<\/strong><\/p>\n\n\n<iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/5\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/5\">create.withcode.uk<\/a><\/iframe>\n\n\n<div class=\"su-spoiler su-spoiler-style-default su-spoiler-icon-plus su-spoiler-closed\" data-scroll-offset=\"0\" data-anchor-in-url=\"no\"><div class=\"su-spoiler-title\" tabindex=\"0\" role=\"button\"><span class=\"su-spoiler-icon\"><\/span>Cliquer sur le + pour obtenir la r\u00e9ponse :<\/div><div class=\"su-spoiler-content su-u-clearfix su-u-trim\"><iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/Btm\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/Btm\">create.withcode.uk<\/a><\/iframe><\/div><\/div>\n\n\n\n<p><strong><em>Exercice 4<\/em><\/strong><\/p>\n\n\n\n<p><strong>\u00c9crire un programme qui affiche les 300 premiers nombres. Puis les 300 premiers nombres pairs.<\/strong><\/p>\n\n\n<iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/5\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/5\">create.withcode.uk<\/a><\/iframe>\n\n\n<div class=\"su-spoiler su-spoiler-style-default su-spoiler-icon-plus su-spoiler-closed\" data-scroll-offset=\"0\" data-anchor-in-url=\"no\"><div class=\"su-spoiler-title\" tabindex=\"0\" role=\"button\"><span class=\"su-spoiler-icon\"><\/span>Cliquer sur le + pour obtenir la r\u00e9ponse :<\/div><div class=\"su-spoiler-content su-u-clearfix su-u-trim\"><iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/Btn\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/Btn\">create.withcode.uk<\/a><\/iframe><\/div><\/div>\n\n\n\n<p><strong><em>Exercice 5<\/em><\/strong><\/p>\n\n\n\n<p><strong>Tester et d\u00e9rouler le programme suivant. C&rsquo;est-\u00e0-dire expliquer le r\u00f4le de chaque instruction.<\/strong><\/p>\n\n\n<iframe frameborder=\"0\" width=\"100%\" height=\"400px\" src=\"https:\/\/create.withcode.uk\/embed\/Btp\"><a target=\"_blank\" href=\"https:\/\/create.withcode.uk\/python\/Btp\">create.withcode.uk<\/a><\/iframe>\n\n\n\n<div class=\"su-spoiler su-spoiler-style-default su-spoiler-icon-plus su-spoiler-closed\" data-scroll-offset=\"0\" data-anchor-in-url=\"no\"><div class=\"su-spoiler-title\" tabindex=\"0\" role=\"button\"><span class=\"su-spoiler-icon\"><\/span>Cliquer sur le + pour obtenir la r\u00e9ponse :<\/div><div class=\"su-spoiler-content su-u-clearfix su-u-trim\">R\u00e9ponse en vid\u00e9o<\/p>\n\n\n\n<figure class=\"wp-block-embed-youtube wp-block-embed is-type-rich is-provider-prise-en-charge-des-contenus-embarques wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe title=\"Les boucles - ex5\" width=\"1040\" height=\"585\" src=\"https:\/\/www.youtube.com\/embed\/5gYkiw1Hndo?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<\/div><\/div>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><div class=\"su-button-center\"><a href=\"http:\/\/mathquiz.fr\/?page_id=860\" class=\"su-button su-button-style-3d\" style=\"color:#FFFFFF;background-color:#2D89EF;border-color:#246ec0;border-radius:9px\" target=\"_self\"><span style=\"color:#FFFFFF;padding:0px 24px;font-size:18px;line-height:36px;border-color:#6cadf4;border-radius:9px;text-shadow:none\"> Cours pr\u00e9c\u00e9dent<\/span><\/a><\/div><br><br><\/td><td><div class=\"su-button-center\"><a href=\"http:\/\/mathquiz.fr\/?page_id=864\" class=\"su-button su-button-style-3d\" style=\"color:#FFFFFF;background-color:#2D89EF;border-color:#246ec0;border-radius:9px\" target=\"_self\"><span style=\"color:#FFFFFF;padding:0px 24px;font-size:18px;line-height:36px;border-color:#6cadf4;border-radius:9px;text-shadow:none\"> Suite du cours<\/span><\/a><\/div><br><br><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Afin de suivi le cours\/TD plus agr\u00e9able, je vous conseille de lire le guide vid\u00e9o disponible en cliquant sur l&rsquo;image ci-dessous. Vous pouvez par ailleurs optimiser votre espace de travail en ouvrant une fen\u00eatre consacr\u00e9[&#8230;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":851,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"https:\/\/mathquiz.fr\/index.php?rest_route=\/wp\/v2\/pages\/862"}],"collection":[{"href":"https:\/\/mathquiz.fr\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/mathquiz.fr\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/mathquiz.fr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mathquiz.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=862"}],"version-history":[{"count":18,"href":"https:\/\/mathquiz.fr\/index.php?rest_route=\/wp\/v2\/pages\/862\/revisions"}],"predecessor-version":[{"id":1513,"href":"https:\/\/mathquiz.fr\/index.php?rest_route=\/wp\/v2\/pages\/862\/revisions\/1513"}],"up":[{"embeddable":true,"href":"https:\/\/mathquiz.fr\/index.php?rest_route=\/wp\/v2\/pages\/851"}],"wp:attachment":[{"href":"https:\/\/mathquiz.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=862"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}