49 lines
2 KiB
HTML
49 lines
2 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="yield sequence">
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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 yield sequence</H1>
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<p>Îïåðàòîð yield sequence èñïîëüçóåòñÿ â ôóíêöèÿõ, ãåíåðèðóþùèõ ïîñëåäîâàòåëüíîñòè,
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âìåñòå ñ <a href="yield.html">îïåðàòîðîì yield</a>, è
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èìååò âèä:</p>
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<blockquote>
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<p><b><code>yield sequence</code></b> <i>âûðàæåíèå</i></p>
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</blockquote>
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<p> îòëè÷èå îò <a href="yield.html">îïåðàòîðà yield</a>, îïåðàòîð yield
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sequence ïåðåáèðàåò ýëåìåíòû ïîñëåäîâàòåëüíîñòè, óêàçàííîé â âûðàæåíèè è
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âîçâðàùàåò ýòè ýëåìåíòû â êà÷åñòâå çíà÷åíèé îñíîâíîé ôóíêöèè-èòåðàòîðà.
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Íàïðèìåð, ñëåäóþùèé êîä:</p>
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<blockquote>
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<p><code><strong>function</strong> f: <strong>sequence of</strong> real;<br>
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<strong>begin</strong><br> <strong>yield</strong> <strong>sequence</strong>
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Seq(1,2,3);<br> <strong>yield</strong> 4;<br><strong>end</strong>;<br>
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<br><strong>begin</strong><br> f.Println;<br><strong>end</strong>. </code></p>
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</blockquote>
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<p>âûâåäåò ïîñëåäîâàòåëüíîñòü</p>
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<blockquote>
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<p><code>1 2 3 4 </code></p>
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</blockquote>
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<p>Ñëåäóþùèé ïðèìåð èëëþñòðèðóåò ôîðìèðîâàíèå ïîñëåäîâàòåëüíîñòè ýëåìåíòîâ ïðè
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îáõîäå áèíàðíîãî äåðåâà â èíôèêñíîì ïîðÿäêå:</p>
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<blockquote>
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<p><code><strong>function</strong> InfixPrintTree<T>(root: Node<T>): <strong>
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sequence of</strong> T;<br><strong>begin</strong><br> <strong>if</strong>
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root = nil <strong>then</strong> exit;<br> <strong>yield</strong>
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<strong>sequence</strong> InfixPrintTree(root.left);<br> <strong>yield</strong>
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root.data;<br> <strong>yield</strong> <strong>sequence</strong>
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InfixPrintTree(root.right);<br><strong>end</strong>;</code></p>
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</blockquote>
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<p>Äëÿ ôóíêöèé, â òåëå êîòîðûõ ïðèñóòñòâóþò yield sequence, äåéñòâóþò òå æå
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îãðàíè÷åíèÿ, ÷òî è äëÿ ôóíêöèé ñ yield.</p>
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</body>
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</html>
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