3240593d2e
Исправлена ошибка for step Дополнена справка по for step и foreach index J,yjdkty ntrcnjdsq htlfrnjh? gjlcdtxbdf.obq ыеуз b штвуч rjyntrcnyj d hfvrf[ jlyjq cnhjrb
87 lines
3.3 KiB
HTML
87 lines
3.3 KiB
HTML
<html>
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<head>
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<object type="application/x-oleobject" classid="clsid:1e2a7bd0-dab9-11d0-b93a-00c04fc99f9e">
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<param name="Keyword" value="foreach">
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<param name="Keyword" value="in">
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<param name="Keyword" value="index">
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</object>
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<meta http-equiv="Content-Type" content="text/html; charset=windows-1251">
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<title></title>
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<link rel="StyleSheet" href="../../default.css">
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</head>
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<body>
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<H1>Îïåðàòîð öèêëà foreach</H1>
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<p>Îïåðàòîð öèêëà <code><b>foreach</b></code> èìååò îäíó èç ñëåäóþùèõ
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ôîðì:</p>
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<blockquote>
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<p><code><b>foreach</b> </code><code class="codeit">ïåðåìåííàÿ</code><code>
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<b>in</b> </code><code class="codeit">êîíòåéíåð</code><code> <b>[index </b>
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<em>ïåðåìåííàÿ</em><strong>]</strong> <b>do</b><br>
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</code><code class="codeit">îïåðàòîð</code></p>
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</blockquote>
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<p>èëè</p>
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<blockquote>
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<p><code><b>foreach</b> </code><code class="codeit">ïåðåìåííàÿ</code><code>:</code><code class="codeit">
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òèï</code><code> <b>in</b> </code><code class="codeit">êîíòåéíåð</code><code>
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<b>[index </b><em>ïåðåìåííàÿ</em><strong>]</strong>
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<b>do</b><br>
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</code><code class="codeit">îïåðàòîð</code></p>
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</blockquote>
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<p>èëè</p>
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<blockquote>
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<p><code><b>foreach</b> <strong>var</strong> </code><code class="codeit">ïåðåìåííàÿ</code><code> <b>in</b> </code><code class="codeit">êîíòåéíåð</code><code>
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<b>[index </b><em>ïåðåìåííàÿ</em><strong>]</strong>
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<b>do</b><br>
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</code><code class="codeit">îïåðàòîð</code></p>
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</blockquote>
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<p> êà÷åñòâå êîíòåéíåðà ìîæåò ôèãóðèðîâàòü äèíàìè÷åñêèé ìàññèâ,
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ñòðîêà, ìíîæåñòâî, à òàêæå ëþáîé êîíòåéíåð, óäîâëåòâîðÿþùèé èíòåðôåéñó
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<code>IEnumerable</code> èëè
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<code>IEnumerable<T></code>(íàïðèìåð, <code>List<T></code>,
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<code>Dictionary<Key,Value></code> è ò.ä.). Ïåðåìåííàÿ öèêëà
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äîëæíà èìåòü òèï, <strong>ñîâïàäàþùèé</strong> ñ òèïîì ýëåìåíòîâ êîíòåéíåðà
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(åñëè êîíòåéíåð óäîâëåòâîðÿåò èíòåðôåéñó
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<code>IEnumerable</code>, òî ýòî òèï <code>object</code>). Â ïîñëåäíåé ôîðìå
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<code><strong>foreach</strong></code> òèï ïåðåìåííîé öèêëà àâòîâûâîäèòñÿ ïî òèïó ýëåìåíòîâ
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êîíòåéíåðà.</p>
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<p>Íåîáÿçàòåëüíàÿ ÷àñòü <code>
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<b>index </b><em>ïåðåìåííàÿ</em></code> ââîäèò ïåðåìåííóþ, êîòîðàÿ õðàíèò íà
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êàæäîé èòåðàöèè èíäåêñ ýëåìåíòà êîíòåéíåðà (ýëåìåíòû èíäåêñèðóþòñÿ ñ íóëÿ).</p>
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<p>Ïåðåìåííàÿ öèêëà ïðîáåãàåò âñå
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çíà÷åíèÿ ýëåìåíòîâ êîíòåéíåðà è äëÿ êàæäîãî çíà÷åíèÿ ïåðåìåííîé
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öèêëà âûïîëíÿåòñÿ òåëî öèêëà. Èçìåíåíèå ïåðåìåííîé öèêëà
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âíóòðè òåëà öèêëà íå ìåíÿåò ýëåìåíòû êîíòåéíåðà, ò.å. îíè äîñòóïíû òîëüêî íà
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÷òåíèå.</p>
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<p>Íàïðèìåð:</p>
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<blockquote>
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<p><code><b>var</b> <br>
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ss: <b>set of</b> string := ['Èâàíîâ','Ïåòðîâ','Ñèäîðîâ'];<b><br>
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</b> a: <b>array of</b> integer := (3,4,5);<br>
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b: <b>array</b> [1..5] <b>of</b> integer := (1,3,5,7,9);<br>
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l := new List<real>;<br>
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<b>begin<br>
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foreach</b> s: string <b>in</b> ss <b>do</b><br>
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write(s,' ');<br>
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writeln;<br>
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<b>
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foreach</b> x: integer <b>in</b> a <b>do</b><br>
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write(x,' ');<br>
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writeln;<br>
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<b>
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foreach</b> <strong>var </strong>x <b>in</b> b <b>do</b><br>
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write(x,' ');<br>
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writeln;<br>
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<b>
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foreach</b> <strong>var</strong> r <b>in</b> l <b>do</b><br>
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write(r,' ');<br>
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<b>end</b>.<br>
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</code></p>
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</blockquote>
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<p> </p>
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</body>
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</html>
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