blocks|key|434065|text|您尚未为set_intersection提供输出迭代器|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|434066|template+<class+InputIterator1,+class+InputIterator2,+class+OutputIterator>
OutputIterator+set_intersection+(+InputIterator1+first1,+InputIterator1+last1,
++++++++++++++++++++++++++++++++++InputIterator2+first2,+InputIterator2+last2,
++++++++++++++++++++++++++++++++++OutputIterator+result+);|code-block|syntax|javascript|434067|通过执行如下操作来修复此问题|434068|...;
set<int>+intersect;
set_intersection(s1.begin(),+s1.end(),+s2.begin(),+s2.end(),
+++++++++++++++++std::inserter(intersect,+intersect.begin()));|434069|您需要一个std::insert迭代器，因为集合现在是空的。我们不能使用std::back_inserter或std::front_inserter，因为set不支持这些操作。|434070|entityMap|0|LINK|mutability|MUTABLE|url|https://en.cppreference.com/w/cpp/algorithm/set_intersection^0|4|G|4|G|0|0|0|0|0|5|B|10|I|1J|J|0^^$0|@$1|2|3|4|5|6|7|Y|8|@$9|Z|A|10|B|C]]|D|@$9|11|A|12|1|13]]|E|$]]|$1|F|3|G|5|H|7|14|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|15|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|16|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|17|8|@$9|18|A|19|B|C]|$9|1A|A|1B|B|C]|$9|1C|A|1D|B|C]]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|1E|8|@]|D|@]|E|$]]]|R|$S|$5|T|U|V|E|$W|X]]]]

You haven't provided an output iterator for <a href="https://en.cppreference.com/w/cpp/algorithm/set_intersection" rel="noreferrer"><code>set_intersection</code></a>
<pre class="lang-cpp prettyprint-override"><code>template &lt;class InputIterator1, class InputIterator2, class OutputIterator&gt;
OutputIterator set_intersection ( InputIterator1 first1, InputIterator1 last1,
 InputIterator2 first2, InputIterator2 last2,
 OutputIterator result );
</code></pre>
Fix this by doing something like
<pre class="lang-cpp prettyprint-override"><code>...;
set&lt;int&gt; intersect;
set_intersection(s1.begin(), s1.end(), s2.begin(), s2.end(),
 std::inserter(intersect, intersect.begin()));
</code></pre>
You need a <code>std::insert</code> iterator since the set is as of now empty. We cannot use <code>std::back_inserter</code> or <code>std::front_inserter</code> since set doesn't support those operations.

blocks|key|434091|text|请查看链接中的示例：http://en.cppreference.com/w/cpp/algorithm/set_intersection|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|434092|您需要另一个容器来存储交叉点数据，下面的代码假定可以工作：|434093|std::vector<int>+common_data;
set_intersection(s1.begin(),s1.end(),s2.begin(),s2.end(),+std::back_inserter(common_data));|code-block|syntax|javascript|434094|entityMap|0|LINK|mutability|MUTABLE|url|http://en.cppreference.com/w/cpp/algorithm/set_intersection^0|A|1N|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|6|7|W|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|X|8|@]|9|@]|C|$I|J]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

Have a look at the sample in the link:
<a href="http://en.cppreference.com/w/cpp/algorithm/set_intersection">http://en.cppreference.com/w/cpp/algorithm/set_intersection</a>

You need another container to store the intersection data, below code suppose to work:

<pre><code>std::vector&lt;int&gt; common_data;
set_intersection(s1.begin(),s1.end(),s2.begin(),s2.end(), std::back_inserter(common_data));
</code></pre>

blocks|key|434145|text|参见std::set_intersection。您必须添加一个输出迭代器，您将在其中存储结果：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|434146|#include+<iterator>
std::vector<int>+s3;
set_intersection(s1.begin(),s1.end(),s2.begin(),s2.end(),+std::back_inserter(s3));|code-block|syntax|javascript|434147|完整列表请参见Ideone。|434148|entityMap|0|LINK|mutability|MUTABLE|url|http://www.cplusplus.com/reference/algorithm/set_intersection/|1|http://ideone.com/aDhCOe^0|2|L|0|0|0|7|6|1|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@$A|10|B|11|1|12]]|C|$]]|$1|K|3|-4|5|6|7|13|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]|S|$5|N|O|P|C|$Q|T]]]]

See <a href="http://www.cplusplus.com/reference/algorithm/set_intersection/" rel="noreferrer">std::set_intersection</a>. You must add an output iterator, where you will store the result:

<pre><code>#include &lt;iterator&gt;
std::vector&lt;int&gt; s3;
set_intersection(s1.begin(),s1.end(),s2.begin(),s2.end(), std::back_inserter(s3));
</code></pre>

See <a href="http://ideone.com/aDhCOe" rel="noreferrer">Ideone</a> for full listing.

blocks|key|216120|text|只需在这里评论。我认为是时候在set接口中添加并集、交集操作了。让我们在未来的标准中提出这一点。我已经使用std很长时间了，每次我使用set操作时，我都希望std更好。对于一些复杂的集合操作，比如intersect，你可以简单地(更容易？)修改以下代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|216121|template+<class+InputIterator1,+class+InputIterator2,+class+OutputIterator>
++OutputIterator+set_intersection+(InputIterator1+first1,+InputIterator1+last1,
+++++++++++++++++++++++++++++++++++InputIterator2+first2,+InputIterator2+last2,
+++++++++++++++++++++++++++++++++++OutputIterator+result)
{
++while+(first1!=last1+&&+first2!=last2)
++{
++++if+(*first1<*first2)+%2B%2Bfirst1;
++++else+if+(*first2<*first1)+%2B%2Bfirst2;
++++else+{
++++++*result+=+*first1;
++++++%2B%2Bresult;+%2B%2Bfirst1;+%2B%2Bfirst2;
++++}
++}
++return+result;
}|code-block|syntax|javascript|216122|从http://www.cplusplus.com/reference/algorithm/set_intersection/复制|offset|length|216123|例如，如果你的输出是一个集合，你可以output.insert(*first1)。此外，您的函数可能不是templated.If您的代码可以比使用std+set_intersection函数更短，然后继续使用它。|216124|如果你想做两个集合的联合，你可以简单地setA.insert(setB.begin()，setB.end())；这比set_union方法简单得多。但是，这不适用于向量。|216125|entityMap|0|LINK|mutability|MUTABLE|url|http://www.cplusplus.com/reference/algorithm/set_intersection/^0|0|0|1|1Q|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@$I|Z|J|10|1|11]]|A|$]]|$1|K|3|L|5|6|7|12|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

Just comment here. I think it is time to add union, intersect operation to the set interface. Let's propose this in the future standards. I have been using the std for a long time, each time I used the set operation I wished the std were better. For some complicated set operation, like intersect, you may simply (easier?) modify the following code:

<pre><code>template &lt;class InputIterator1, class InputIterator2, class OutputIterator&gt;
 OutputIterator set_intersection (InputIterator1 first1, InputIterator1 last1,
 InputIterator2 first2, InputIterator2 last2,
 OutputIterator result)
{
 while (first1!=last1 &amp;&amp; first2!=last2)
 {
 if (*first1&lt;*first2) ++first1;
 else if (*first2&lt;*first1) ++first2;
 else {
 *result = *first1;
 ++result; ++first1; ++first2;
 }
 }
 return result;
}
</code></pre>

copied from <a href="http://www.cplusplus.com/reference/algorithm/set_intersection/" rel="nofollow noreferrer">http://www.cplusplus.com/reference/algorithm/set_intersection/</a>

For example, if your output is a set, you can output.insert(*first1). Furthermore, you function may not be templated.If you code can be shorter than using the std set_intersection function then go ahead with it.

If you want to do a union of two set you can simply setA.insert(setB.begin(), setB.end()); This is much simpler than the set_union method. However, this will not work with vector.

I have been trying to find the intersection between two std::set in C++, but I keep getting an error.

I created a small sample test for this

<pre><code>#include &lt;iostream&gt;
#include &lt;vector&gt;
#include &lt;algorithm&gt;
#include &lt;set&gt;
using namespace std;

int main() {
 set&lt;int&gt; s1;
 set&lt;int&gt; s2;

 s1.insert(1);
 s1.insert(2);
 s1.insert(3);
 s1.insert(4);

 s2.insert(1);
 s2.insert(6);
 s2.insert(3);
 s2.insert(0);

 set_intersection(s1.begin(),s1.end(),s2.begin(),s2.end());
 return 0;
}
</code></pre>

The latter program does not generate any output, but I expect to have a new set (let's call it <code>s3</code>) with the following values:

<pre><code>s3 = [ 1 , 3 ]
</code></pre>

Instead I'm getting the error:

<pre><code>test.cpp: In function ‘int main()’:
test.cpp:19: error: no matching function for call to ‘set_intersection(std::_Rb_tree_const_iterator&lt;int&gt;, std::_Rb_tree_const_iterator&lt;int&gt;, std::_Rb_tree_const_iterator&lt;int&gt;, std::_Rb_tree_const_iterator&lt;int&gt;)’
</code></pre>

What I understand out of this error, is that there's no definition in <code>set_intersection</code> that accepts <code>Rb_tree_const_iterator&lt;int&gt;</code> as parameter. 

Furthermore, I suppose the <code>std::set.begin()</code> method returns an object of such type, 

is there a better way to find the intersection of two <code>std::set</code> in C++? Preferably a built-in function? 

Thanks a lot!

how to find the intersection of two std::set in C++?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我一直试图在C++中查找两个std::set之间的交叉点，但是我总是得到一个错误。我为此创建了一个小样本测试#include <iostream>#include <vector>#include <algorithm>#include <set>using namespace std;int main() { se...

问如何在C++中找到两个std::set的交集？
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问如何在C++中找到两个std::set的交集？EN