blocks|key|1039740|text|std::qsort继承自标准C库。这是行不通的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1039741|您需要使用std::sort对字符串进行排序。|1039742|具体地说，先将std::string转换为void*，然后再转换为char*，这是未定义的，不会起作用。|1039743|entityMap|0|LINK|mutability|MUTABLE|url|http://en.cppreference.com/w/cpp/algorithm/qsort|1|http://en.cppreference.com/w/cpp/algorithm/sort^0|0|A|0|A|0|0|5|9|5|9|1|0|7|B|L|5|X|5|0^^$0|@$1|2|3|4|5|6|7|T|8|@$9|U|A|V|B|C]]|D|@$9|W|A|X|1|Y]]|E|$]]|$1|F|3|G|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@$9|12|A|13|1|14]]|E|$]]|$1|H|3|I|5|6|7|15|8|@$9|16|A|17|B|C]|$9|18|A|19|B|C]|$9|1A|A|1B|B|C]]|D|@]|E|$]]|$1|J|3|-4|5|6|7|1C|8|@]|D|@]|E|$]]]|K|$L|$5|M|N|O|E|$P|Q]]|R|$5|M|N|O|E|$P|S]]]]

<a href="http://en.cppreference.com/w/cpp/algorithm/qsort" rel="nofollow noreferrer"><code>std::qsort</code></a> is inherited from the standard C library. It will not work.

You need to use <a href="http://en.cppreference.com/w/cpp/algorithm/sort" rel="nofollow noreferrer"><code>std::sort</code></a> for sorting strings.

Specifically, cast <code>std::string</code> to <code>void*</code> and then to <code>char*</code> is undefined and won't work.

blocks|key|1039775|text|这是C%2B%2B，不是C。对字符串数组进行排序很容易。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1039776|#include+<string>
#include+<vector>
#include+<algorithm>

std::vector<std::string>+stringarray;
std::sort(stringarray.begin(),+stringarray.end());|code-block|syntax|javascript|1039777|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This is C++, not C. Sorting an array of strings is easy.

<pre><code>#include &lt;string&gt;
#include &lt;vector&gt;
#include &lt;algorithm&gt;

std::vector&lt;std::string&gt; stringarray;
std::sort(stringarray.begin(), stringarray.end());
</code></pre>

blocks|key|1254762|text|CPP中的算法sort与qsort具有相同的复杂度：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1254763|#include+<iostream>
#include+<algorithm>
#include+<vector>
#include+<string>
using+namespace+std;

bool+compare(string+a,+string+b){
++++cout+<<+"compare("+<<+a+<<+","+<<+b+<<+")"+<<+endl;
++++return+(a.compare(b)+<+0);
}

int+main+()+{

++++string+mystrs[]+=+{"www","ggg","bbb","ssss","aaa"};
++++vector<string>+myvector+(mystrs,+mystrs+%2B+5);+++++++++++++++
++++vector<string>::iterator+it;

++sort+(myvector.begin(),+myvector.end(),+compare);

++cout+<<+"vector+contains:";
++for+(it=myvector.begin();+it!=myvector.end();+%2B%2Bit)
++++cout+<<+"+"+<<+*it;

++cout+<<+endl;

++return+0;
}|code-block|syntax|javascript|1254764|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

algorithm sort in CPP has the same complexity as qsort:

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

bool compare(string a, string b){
 cout &lt;&lt; "compare(" &lt;&lt; a &lt;&lt; "," &lt;&lt; b &lt;&lt; ")" &lt;&lt; endl;
 return (a.compare(b) &lt; 0);
}

int main () {

 string mystrs[] = {"www","ggg","bbb","ssss","aaa"};
 vector&lt;string&gt; myvector (mystrs, mystrs + 5); 
 vector&lt;string&gt;::iterator it;

 sort (myvector.begin(), myvector.end(), compare);

 cout &lt;&lt; "vector contains:";
 for (it=myvector.begin(); it!=myvector.end(); ++it)
 cout &lt;&lt; " " &lt;&lt; *it;

 cout &lt;&lt; endl;

 return 0;
}
</code></pre>

blocks|key|1039916|text|您可以使用boost::sort，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1039917|#include+<vector>
#include+<boost/range/algorithm.hpp>

std::vector<std::string>+stringarray;
boost::sort(stringarray);|code-block|syntax|javascript|1039918|如果要使用find，请使用boost::find，如下所示：|1039919|std::string+findme;
auto+offset+=+boost::find(stringarray,+findme)+-+stringarray.begin()|1039920|查看两个有用的函数(m_stringarray应该是ClassA的成员)：|1039921|const+size_t+ClassA::GetIdByName(std::string+name)+const
{
++++return+(boost::find(this->m_stringarray,+name)+-+this->m_stringarray.begin());
}

const+std::string+ClassA::GetNameById(size_t+id)+const
{
++++return+this->m_stringarray[id];
}|1039922|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

You can use boost::sort, like this:

<pre><code>#include &lt;vector&gt;
#include &lt;boost/range/algorithm.hpp&gt;

std::vector&lt;std::string&gt; stringarray;
boost::sort(stringarray);
</code></pre>

If you want use find use boost::find, like this:

<pre><code>std::string findme;
auto offset = boost::find(stringarray, findme) - stringarray.begin()
</code></pre>

See 2 useful functions (m_stringarray should be member of ClassA):

<pre><code>const size_t ClassA::GetIdByName(std::string name) const
{
 return (boost::find(this-&gt;m_stringarray, name) - this-&gt;m_stringarray.begin());
}

const std::string ClassA::GetNameById(size_t id) const
{
 return this-&gt;m_stringarray[id];
}
</code></pre>

blocks|key|1254890|text|正如这里的许多人所说的，您可以使用std::sort进行排序，但是当您想要从z-a排序时会发生什么呢？这段代码可能很有用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1254891|bool+cmp(string+a,+string+b)
{
if(a.compare(b)+>+0)
++++return+true;
else
++++return+false;
}

int+main()
{
string+words[]+=+{"this",+"a",+"test",+"is"};
int+length+=+sizeof(words)+/+sizeof(string);
sort(words,+words+%2B+length,+cmp);

for(int+i+=+0;+i+<+length;+i%2B%2B)
++++cout+<<+words[i]+<<+"+";
cout+<<+endl;
++++//+output+will+be:+this+test+is+a+

}|code-block|syntax|javascript|1254892|如果想颠倒排序顺序，只需修改cmp函数中的符号即可。|1254893|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

As many here have stated, you could use std::sort to sort, but what is going to happen when you, for instance, want to sort from z-a? This code may be useful

<pre><code>bool cmp(string a, string b)
{
if(a.compare(b) &gt; 0)
 return true;
else
 return false;
}

int main()
{
string words[] = {"this", "a", "test", "is"};
int length = sizeof(words) / sizeof(string);
sort(words, words + length, cmp);

for(int i = 0; i &lt; length; i++)
 cout &lt;&lt; words[i] &lt;&lt; " ";
cout &lt;&lt; endl;
 // output will be: this test is a 

}
</code></pre>

If you want to reverse the order of sorting just modify the sign in the cmp function.

I am trying to sort an array of strings, but it's not sorting anything.... what am I doing wrong?

<pre><code>string namesS[MAX_NAMES];

int compare (const void * a, const void * b){
 return ( *(char*)a - *(char*)b );
}


void sortNames(){

 qsort(namesS, MAX_NAMES, sizeof(string), compare);
}
</code></pre>

C++ sort array of strings

我正在尝试对字符串数组进行排序，但它没有对任何内容进行排序...我做错了什么？string namesS[MAX_NAMES];int compare (const void * a, const void * b){    return ( *(char*)a - *(char*)b );}void sortName...

问字符串数组的C++排序
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