blocks|key|3010213|text|std::string::c_str()为您提供了一个const+char*指针，指向表示字符串的字符数组(以null结尾)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3010214|您不应操作此指针所指向的数据，因此，如果需要这样做，请复制数据。|3010215|双重编辑--在更具C%2B%2B风格的中进行编辑|BOLD|3010216|由于在可能的情况下避免使用原始指针和数组更好，因此还可以将数据放入std::vector<char>中|3010217|#include+<string>
#include+<vector>

int+main()
{
++++std::string+str+=+"Hello";
++++std::vector<char>+cvec(str.begin(),+str.end());+

++++//+do+stuff
}|code-block|syntax|javascript|3010218|编辑这更类似于C，因为它使用原始指针并显式地分配mem|3010219|#include+<string>
#include+<cstring>

int+main()
{
++++std::string+str+=+"Hello";
++++char+*cptr+=+new+char[str.size()%2B1];+//+%2B1+to+account+for+\0+byte
++++std::strncpy(cptr,+str.c_str(),+str.size());

++++//+do+stuff...
++++delete+[]+cptr;
}|3010220|entityMap^0|0|K|R|B|0|0|0|F|0|X|H|0|0|0|R|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@$9|Y|A|Z|B|C]|$9|10|A|11|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|12|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|13|8|@$9|14|A|15|B|J]]|D|@]|E|$]]|$1|K|3|L|5|6|7|16|8|@$9|17|A|18|B|C]]|D|@]|E|$]]|$1|M|3|N|5|O|7|19|8|@]|D|@]|E|$P|Q]]|$1|R|3|S|5|6|7|1A|8|@$9|1B|A|1C|B|J]]|D|@]|E|$]]|$1|T|3|U|5|O|7|1D|8|@]|D|@]|E|$P|Q]]|$1|V|3|-4|5|6|7|1E|8|@]|D|@]|E|$]]]|W|$]]

<code>std::string::c_str()</code> gets you a <code>const char*</code> pointer to a character array that represents the string (null-terminated).

You should not manipulate the data this pointer points to, so if you need to do that, copy the data.

Double edit - doing it in a more C++ fashion

Since it is nicer to avoid the use of raw pointers and arrays where possible, you can also get the data into an <code>std::vector&lt;char&gt;</code>

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

int main()
{
 std::string str = "Hello";
 std::vector&lt;char&gt; cvec(str.begin(), str.end()); 

 // do stuff
}
</code></pre>

edit this is more like C since it uses raw pointers and explicitly allocates mem

<pre><code>#include &lt;string&gt;
#include &lt;cstring&gt;

int main()
{
 std::string str = "Hello";
 char *cptr = new char[str.size()+1]; // +1 to account for \0 byte
 std::strncpy(cptr, str.c_str(), str.size());

 // do stuff...
 delete [] cptr;
}
</code></pre>

blocks|key|293760|text|使用foobar.c_str()。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|293761|你可能会发现这个链接很有用：http://www.cppreference.com/wiki/string/start|293762|entityMap|0|LINK|mutability|MUTABLE|url|http://www.cppreference.com/wiki/string/start^0|2|E|0|E|19|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|S|8|@]|D|@$9|T|A|U|1|V]]|E|$]]|$1|H|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

Use <code>foobar.c_str()</code>.

You might find this link useful: <a href="http://www.cppreference.com/wiki/string/start" rel="noreferrer">http://www.cppreference.com/wiki/string/start</a>

blocks|key|3010259|text|const+char*+foobar2+=+foobar.c_str();|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3010260|请注意const。否则，您必须将其复制到char缓冲区。|unstyled|offset|length|style|BOLD|3010261|entityMap^0|0|3|5|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@$G|O|H|P|I|J]]|9|@]|A|$]]|$1|K|3|-4|5|F|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>const char* foobar2 = foobar.c_str();
</code></pre>

Notice the const.
Otherwise you have to copy it to a char buffer.

blocks|key|293768|text|你会在这里得到很多关于str.c_str()的不正确的答案。:)虽然c_str()确实很有用，但请记住，这实际上不会将字符串转换为char*，而是将字符串的内容作为const+char*返回。和这是一个很大的区别！|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|CODE|entityRanges|data|293769|这里重要的是，仅当给定的string对象存在时，从c_str()获得的指针才有效。所以这将是非常错误的|293770|class+Something+{
++++const+char*+name;
public:
++++Something(const+std::string&+pname)+{
++++++++this->name+=+pname.c_str();+/*+wrong!+the+pointer+will+go+wrong+as+the+object+from+the+parameter+ceases+to+exist+*/
++++}
};|code-block|syntax|javascript|293771|因此，如果您想要创建一个独立于原始std::string，的新值，如:创建一个独立于原始的新值，那么您需要执行以下操作：|293772|char*+convert(const+std::string&+str)+{
++++char*+result+=+new+char[str.length()%2B1];
++++strcpy(result,str.c_str());
++++return+result;
}|293773|但是在大多数情况下，c_str()对你来说已经足够了。试着用物体的寿命来思考。|293774|entityMap^0|9|I|2O|B|B|B|Y|7|1T|5|2A|B|0|C|6|P|7|0|0|H|B|T|F|H|B|0|0|A|7|0^^$0|@$1|2|3|4|5|6|7|V|8|@$9|W|A|X|B|C]|$9|Y|A|Z|B|C]|$9|10|A|11|B|D]|$9|12|A|13|B|D]|$9|14|A|15|B|D]|$9|16|A|17|B|D]]|E|@]|F|$]]|$1|G|3|H|5|6|7|18|8|@$9|19|A|1A|B|D]|$9|1B|A|1C|B|D]]|E|@]|F|$]]|$1|I|3|J|5|K|7|1D|8|@]|E|@]|F|$L|M]]|$1|N|3|O|5|6|7|1E|8|@$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]|$9|1J|A|1K|B|D]]|E|@]|F|$]]|$1|P|3|Q|5|K|7|1L|8|@]|E|@]|F|$L|M]]|$1|R|3|S|5|6|7|1M|8|@$9|1N|A|1O|B|D]]|E|@]|F|$]]|$1|T|3|-4|5|6|7|1P|8|@]|E|@]|F|$]]]|U|$]]

You're going to get a lot of kinda incorrect answers about <code>str.c_str()</code> here. :) While <code>c_str()</code> is indeed useful, please keep in mind that this will not actually convert the string into a <code>char*</code>, but rather return the contents of the string as a <code>const char*</code>. And this is a big difference!

What's important here is that the pointer you obtain from <code>c_str()</code> is valid only as long as the given <code>string</code> object exists. So this would be terribly wrong:

<pre><code>class Something {
 const char* name;
public:
 Something(const std::string&amp; pname) {
 this-&gt;name = pname.c_str(); /* wrong! the pointer will go wrong as the object from the parameter ceases to exist */
 }
};
</code></pre>

So if you want to convert, as in: create a new value which will be independent of the original <code>std::string</code>, then you'll want to do something like this:

<pre><code>char* convert(const std::string&amp; str) {
 char* result = new char[str.length()+1];
 strcpy(result,str.c_str());
 return result;
}
</code></pre>

But still <code>c_str()</code> will be quite enough for you in most cases. Just try to think in terms of objects' time of life.

<blockquote>
 Possible Duplicate: 
 <a href="https://stackoverflow.com/questions/347949/convert-stdstring-to-const-char-or-char">Convert std::string to const char* or char*</a> 
</blockquote>



<pre><code>void Foo::bar(const std::string&amp; foobar) {
 // ...
 const char* foobar2 = (char*)foobar;
 // ...
}
</code></pre>

That does not work and I get an error during compilation about invalid casting.

Is there some other way to convert <code>std::string</code> to <code>const char*</code>?

How to convert std::string to const char*?

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。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋 

腾讯云代码助手

CODING DevOps

Cloud Studio

SDK中心

API中心

命令行工具

 可能重复：void Foo::bar(const std::string& foobar) {    // ...    const char* foobar2 = (char*)foobar;    // ...}这不起作用，并且我在编译过程中得到一个关于无效类型转换的错误。是否有其他方法可以将std::strin...

问如何将std::string转换为const char*？
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何将std::string转换为const char*？EN