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12.4.3 集合成员资格</div>
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约束支持整数值集合以及集合成员资格操作符（在<a href="00568.html" target="topic">7.20节</a>定义）。 </p>
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如果没有其它的约束，<span style="color: #0000FF">inside</span>操作符在选择值的时候，所有的值（包括单一值或范围值）都具有相等的概率。 </p>
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<span style="color: #0000FF">inside</span>操作符的否定形式指示表达式位于集合范围之外：<span style="color: #800080">!(<i></span>expression</i> <span style="color: #0000FF">inside</span> <span style="color: #800080">{<i></span>set<span style="color: #800080"></i>})</span>。 </p>
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例如： </p><div class="Element170">
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<div class="Element13"><div class="Element12" id="code00405"><pre class="Element12"><span style="color: #0000FF">rand integer</span> x<span style="color: #800080">,</span> y<span style="color: #800080">,</span> z<span style="color: #800080">;</span>
<span style="color: #0000FF">constraint</span> c1 <span style="color: #800080">{</span>x <span style="color: #0000FF">inside</span> <span style="color: #800080">{</span><span style="color: #FF0000">3</span><span style="color: #800080">, </span><span style="color: #FF0000">5</span><span style="color: #800080">, [</span><span style="color: #FF0000">9</span><span style="color: #800080">:</span><span style="color: #FF0000">15</span><span style="color: #800080">], [</span><span style="color: #FF0000">24</span><span style="color: #800080">:</span><span style="color: #FF0000">32</span><span style="color: #800080">], [</span>y<span style="color: #800080">:</span><span style="color: #FF0000">2</span><span style="color: #800080">*</span>y<span style="color: #800080">], </span>z<span style="color: #800080">};}</span>
<span style="color: #0000FF">rand integer</span> a<span style="color: #800080">,</span> b<span style="color: #800080">,</span> c<span style="color: #800080">;</span>
<span style="color: #0000FF">constraint</span> c2 <span style="color: #800080">{</span>a <span style="color: #0000FF">inside</span> <span style="color: #800080">{</span>b<span style="color: #800080">, </span>c<span style="color: #800080">};}</span>
<span style="color: #0000FF">integer</span> fives<span style="color: #800080">[</span><span style="color: #FF0000">0</span><span style="color: #800080">:</span><span style="color: #FF0000">3</span><span style="color: #800080">]</span> <span style="color: #800080">= {</span><span style="color: #FF0000">5</span><span style="color: #800080">, </span><span style="color: #FF0000">10</span><span style="color: #800080">, </span><span style="color: #FF0000">15</span><span style="color: #800080">, </span><span style="color: #FF0000">20</span><span style="color: #800080">};</span>
<span style="color: #0000FF">rand integer</span> v<span style="color: #800080">;</span>
<span style="color: #0000FF">constraint</span> c3 <span style="color: #800080">{</span>v <span style="color: #0000FF">inside</span> fives<span style="color: #800080">;}</span></pre></div></div>
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很重要的一点是，我们必须注意：<span style="color: #0000FF">inside</span>操作符是双向的，因此，上面的第二个例子等价于<i>a</i> <span style="color: #800080">==</span> <i>b</i> <span style="color: #800080">||</span> <i>a</i> <span style="color: #800080">==</span> <i>c</i>。</p></div>
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