69 lines
2.6 KiB
HTML
69 lines
2.6 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="if">
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<param name="Keyword" value="then">
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<param name="Keyword" value="else">
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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>Óñëîâíûé îïåðàòîð</H1>
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<p>Óñëîâíûé îïåðàòîð èìååò <i>ïîëíóþ</i> è <i>êðàòêóþ</i> ôîðìû.
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</p>
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<p><i>Ïîëíàÿ ôîðìà óñëîâíîãî îïåðàòîðà</i> âûãëÿäèò ñëåäóþùèì
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îáðàçîì:</p>
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<blockquote>
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<p><b><code>if</code></b> <code class="codeit">óñëîâèå</code> <code><b>then</b></code> <code class="codeit">
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îïåðàòîð1</code><br>
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<code><b>else</b></code> <code class="codeit">îïåðàòîð2</code> </p>
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</blockquote>
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 êà÷åñòâå óñëîâèÿ óêàçûâàåòñÿ íåêîòîðîå ëîãè÷åñêîå âûðàæåíèå. Åñëè óñëîâèå îêàçûâàåòñÿ
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èñòèííûì, òî âûïîëíÿåòñÿ <code class="codeit">îïåðàòîð1</code>, â ïðîòèâíîì
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ñëó÷àå âûïîëíÿåòñÿ <code class="codeit">îïåðàòîð2</code>.<p><i>
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Êðàòêàÿ</i> ôîðìà óñëîâíîãî îïåðàòîðà èìååò âèä:</p>
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<blockquote>
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<p><b><code>if</code></b> <code class="codeit">óñëîâèå</code> <code><b>then</b></code> <code class="codeit">
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îïåðàòîð</code></p>
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</blockquote>
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<p>Åñëè óñëîâèå îêàçûâàåòñÿ èñòèííûì, òî âûïîëíÿåòñÿ <code class="codeit">
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îïåðàòîð</code>, â ïðîòèâíîì ñëó÷àå ïðîèñõîäèò ïåðåõîä ê ñëåäóþùåìó îïåðàòîðó
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ïðîãðàììû.</p>
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<p> ñëó÷àå êîíñòðóêöèè âèäà</p>
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<blockquote>
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<p><b><code>if</code></b> <code class="codeit">óñëîâèå1</code>
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<code><b>then</b></code> <b><code><br>
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</span>if</code></b> <code class="codeit">óñëîâèå2</code>
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<code><b>then</b></code> <code class="codeit">îïåðàòîð1</code><br>
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<code><b> else</b></code> <code class="codeit">
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îïåðàòîð2</code> </p>
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</blockquote>
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<p><code><b>else</b></code> âñåãäà îòíîñèòñÿ ê áëèæàéøåìó
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ïðåäûäóùåìó îïåðàòîðó <code><b>if</b></code>, äëÿ êîòîðîãî âåòêà <code><b>else</b></code>
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åùå íå óêàçàíà. Åñëè â ïðåäûäóùåì ïðèìåðå òðåáóåòñÿ, ÷òîáû
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<code><b>else</b></code> îòíîñèëàñü ê ïåðâîìó îïåðàòîðó
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<code><b>if</b></code>, òî íåîáõîäèìî èñïîëüçîâàòü
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ñîñòàâíîé îïåðàòîð:</p>
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<blockquote>
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<p><b><code>if</code></b> <code class="codeit">óñëîâèå1</code>
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<code><b>then<br>
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begin</b></code> <b><code><br>
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if</code></b> <code class="codeit">óñëîâèå2</code>
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<code><b>then</b></code> <code class="codeit">îïåðàòîð1<br>
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</code><code><b>end</b></code><br>
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<code><b>else</b></code> <code class="codeit">îïåðàòîð2</code> </p>
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</blockquote>
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<p>Íàïðèìåð:</p>
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<blockquote>
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<p><code><b>if</b> a<b <b>then</b><br>
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min := a<br>
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<b>else</b> min := b;</code></p>
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</blockquote>
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</body>
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</html>
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