blocks|key|2388640|text|除非您担心性能问题，否则请使用string+streams|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2388641|#include+<sstream>
//..

std::ostringstream+ss;
ss+<<+myFloat;
std::string+s(ss.str());|code-block|syntax|javascript|2388642|如果你对Boost没意见，lexical_cast<>是一个很方便的选择：|2388643|std::string+s+=+boost::lexical_cast<std::string>(myFloat);|2388644|有效的替代方法是例如FastFormat或简单的C风格的函数。|2388645|entityMap|0|LINK|mutability|MUTABLE|url|http://en.cppreference.com/w/cpp/io/basic_ostream/operator_ltlt|1|http://www.boost.org/doc/libs/1_41_0/libs/conversion/lexical_cast.htm|2|http://www.fastformat.org/^0|F|E|0|0|0|D|E|1|0|0|A|A|2|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@$A|11|B|12|1|13]]|C|$]]|$1|D|3|E|5|F|7|14|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|15|8|@]|9|@$A|16|B|17|1|18]]|C|$]]|$1|K|3|L|5|F|7|19|8|@]|9|@]|C|$G|H]]|$1|M|3|N|5|6|7|1A|8|@]|9|@$A|1B|B|1C|1|1D]]|C|$]]|$1|O|3|-4|5|6|7|1E|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]|W|$5|R|S|T|C|$U|X]]|Y|$5|R|S|T|C|$U|Z]]]]

Unless you're worried about performance, use <a href="http://en.cppreference.com/w/cpp/io/basic_ostream/operator_ltlt" rel="nofollow noreferrer">string streams</a>:

<pre class="lang-cpp prettyprint-override"><code>#include &lt;sstream&gt;
//..

std::ostringstream ss;
ss &lt;&lt; myFloat;
std::string s(ss.str());
</code></pre>

If you're okay with Boost, <a href="http://www.boost.org/doc/libs/1_41_0/libs/conversion/lexical_cast.htm" rel="nofollow noreferrer">lexical_cast&lt;></a> is a convenient alternative:

<pre><code>std::string s = boost::lexical_cast&lt;std::string&gt;(myFloat);
</code></pre>

Efficient alternatives are e.g. <a href="http://www.fastformat.org/" rel="nofollow noreferrer">FastFormat</a> or simply the C-style functions.

blocks|key|8017|text|如果您担心性能问题，请查看Boost::lexical_cast库。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|8018|entityMap|0|LINK|mutability|MUTABLE|url|http://www.boost.org/doc/libs/1_41_0/libs/conversion/lexical_cast.htm^0|D|J|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

If you're worried about performance, check out the <a href="http://www.boost.org/doc/libs/1_41_0/libs/conversion/lexical_cast.htm" rel="nofollow noreferrer">Boost::lexical_cast</a> library.

blocks|key|8034|text|您可以定义一个模板，它不仅适用于doubles，而且还适用于其他类型。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|8035|template+<typename+T>+string+tostr(const+T&+t)+{+
+++ostringstream+os;+
+++os<<t;+
+++return+os.str();+
}+|code-block|syntax|javascript|8036|然后，您可以将其用于其他类型。|8037|double+x+=+14.4;
int+y+=+21;

string+sx+=+tostr(x);
string+sy+=+tostr(y);|8038|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

You can define a template which will work not only just with doubles, but with other types as well.

<pre><code>template &lt;typename T&gt; string tostr(const T&amp; t) { 
 ostringstream os; 
 os&lt;&lt;t; 
 return os.str(); 
} 
</code></pre>

Then you can use it for other types.

<pre><code>double x = 14.4;
int y = 21;

string sx = tostr(x);
string sy = tostr(y);
</code></pre>

blocks|key|979716|text|从C%2B%2B11开始，标准C%2B%2B库为函数std::to_string(arg)提供了arg支持的各种类型。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|979717|entityMap|0|LINK|mutability|MUTABLE|url|http://www.cplusplus.com/reference/string/to_string/^0|I|J|14|3|I|J|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]]|D|@$9|S|A|T|1|U]]|E|$]]|$1|F|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

As of C++11, the standard C++ library provides the function <a href="http://www.cplusplus.com/reference/string/to_string/" rel="noreferrer"><code>std::to_string(arg)</code></a> with various supported types for <code>arg</code>.

blocks|key|979749|text|This+tutorial给出了一个简单而优雅的解决方案，我将其转录如下：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|979750|#include+<sstream>
#include+<string>
#include+<stdexcept>

class+BadConversion+:+public+std::runtime_error+{
public:
++BadConversion(std::string+const&+s)
++++:+std::runtime_error(s)
++++{+}
};

inline+std::string+stringify(double+x)
{
++std::ostringstream+o;
++if+(!(o+<<+x))
++++throw+BadConversion("stringify(double)");
++return+o.str();
}
...
std::string+my_val+=+stringify(val);|code-block|syntax|javascript|979751|entityMap|0|LINK|mutability|MUTABLE|url|http://www.parashift.com/c%2B%2B-faq-lite/convert-num-to-string.html^0|0|D|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

<a href="http://www.parashift.com/c++-faq-lite/convert-num-to-string.html" rel="nofollow">This tutorial</a> gives a simple, yet elegant, solution, which i transcribe:

<pre><code>#include &lt;sstream&gt;
#include &lt;string&gt;
#include &lt;stdexcept&gt;

class BadConversion : public std::runtime_error {
public:
 BadConversion(std::string const&amp; s)
 : std::runtime_error(s)
 { }
};

inline std::string stringify(double x)
{
 std::ostringstream o;
 if (!(o &lt;&lt; x))
 throw BadConversion("stringify(double)");
 return o.str();
}
...
std::string my_val = stringify(val);
</code></pre>

blocks|key|2388844|text|重要|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2388845|阅读结尾处的注释。|2388846|快速解答:|2388847|使用to_string()。(从c%2B%2B11开始提供)|CODE|2388848|示例：|2388849|#include+<iostream>+++
#include+<string>++

using+namespace+std;
int+main+()
{
++++string+pi+=+"pi+is+"+%2B+to_string(3.1415926);
++++cout<<+"pi+=+"<<+pi+<<+endl;

++return+0;
}|code-block|syntax|javascript|2388850|自己运行：http://ideone.com/7ejfaU|2388851|这些也是可用的：|2388852|string+to_string+(int+val);
string+to_string+(long+val);
string+to_string+(long+long+val);
string+to_string+(unsigned+val);
string+to_string+(unsigned+long+val);
string+to_string+(unsigned+long+long+val);
string+to_string+(float+val);
string+to_string+(double+val);
string+to_string+(long+double+val);|2388853|重要说明：|2388854|正如@Michael+Konečn+As正确地指出的那样，使用to_string()充其量是有风险的，很可能会导致意想不到的结果。|2388855|来自http://en.cppreference.com/w/cpp/string/basic_string/to_string：|2388856|使用浮点类型std::to_string的|2388857|可能会产生意外的结果，因为返回字符串中的有效位数可以为零，请参见示例。|blockquote|2388858|2388859|返回值可能与std::cout默认打印的值有很大不同，请参见示例。出于格式化的目的，std::to_string依赖于当前的区域设置，因此从多个线程对std::to_string的并发调用可能导致调用的部分序列化。C%2B%2B17提供了std::to_chars作为一种性能更高的独立于区域设置的替代方案。|2388860|2388861|最好的方法是像在his+answer中演示的@dcp那样使用stringstream：|2388862|以下示例演示了此问题：|2388863|自己运行示例：https://www.jdoodle.com/embed/v0/T4k|2388864|#include+<iostream>
#include+<sstream>
#include+<string>

template+<+typename+Type+>+std::string+to_str+(const+Type+&+t)
{
++std::ostringstream+os;
++os+<<+t;
++return+os.str+();
}

int+main+()
{

++//+more+info+:+https://en.cppreference.com/w/cpp/string/basic_string/to_string
++double++++f+=+23.43;
++double++++f2+=+1e-9;
++double++++f3+=+1e40;
++double++++f4+=+1e-40;
++double++++f5+=+123456789;
++std::string+f_str+=+std::to_string+(f);
++std::string+f_str2+=+std::to_string+(f2);+//+Note:+returns+"0.000000"
++std::string+f_str3+=+std::to_string+(f3);+//+Note:+Does+not+return+"1e%2B40".
++std::string+f_str4+=+std::to_string+(f4);+//+Note:+returns+"0.000000"
++std::string+f_str5+=+std::to_string+(f5);

++std::cout+<<+"std::cout:+"+<<+f+<<+'\n'
++++<<+"to_string:+"+<<+f_str+<<+'\n'
++++<<+"ostringstream:+"+<<+to_str+(f)+<<+"\n\n"
++++<<+"std::cout:+"+<<+f2+<<+'\n'
++++<<+"to_string:+"+<<+f_str2+<<+'\n'
++++<<+"ostringstream:+"+<<+to_str+(f2)+<<+"\n\n"
++++<<+"std::cout:+"+<<+f3+<<+'\n'
++++<<+"to_string:+"+<<+f_str3+<<+'\n'
++++<<+"ostringstream:+"+<<+to_str+(f3)+<<+"\n\n"
++++<<+"std::cout:+"+<<+f4+<<+'\n'
++++<<+"to_string:+"+<<+f_str4+<<+'\n'
++++<<+"ostringstream:+"+<<+to_str+(f4)+<<+"\n\n"
++++<<+"std::cout:+"+<<+f5+<<+'\n'
++++<<+"to_string:+"+<<+f_str5+<<+'\n'
++++<<+"ostringstream:+"+<<+to_str+(f5)+<<+'\n';

++return+0;
}|2388865|输出：|2388866|std::cout:+23.43
to_string:+23.430000
ostringstream:+23.43

std::cout:+1e-09
to_string:+0.000000
ostringstream:+1e-09

std::cout:+1e%2B40
to_string:+10000000000000000303786028427003666890752.000000
ostringstream:+1e%2B40

std::cout:+1e-40
to_string:+0.000000
ostringstream:+1e-40

std::cout:+1.23457e%2B08
to_string:+123456789.000000
ostringstream:+1.23457e%2B08+|2388867|entityMap|0|LINK|mutability|MUTABLE|url|http://ideone.com/7ejfaU|1|http://en.cppreference.com/w/cpp/string/basic_string/to_string|2|https://stackoverflow.com/a/2125908/2736559|3|https://www.jdoodle.com/embed/v0/T4k^0|0|2|0|0|0|5|0|2|B|0|0|0|5|O|0|0|0|0|0|5|0|V|B|0|2|1Q|1|0|6|E|0|0|0|6|9|16|E|23|E|2Z|5|37|D|0|0|U|C|8|A|2|0|0|7|10|3|0|0|0|0^^$0|@$1|2|3|4|5|6|7|24|8|@$9|25|A|26|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|27|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|28|8|@$9|29|A|2A|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|2B|8|@$9|2C|A|2D|B|L]]|D|@]|E|$]]|$1|M|3|N|5|6|7|2E|8|@]|D|@]|E|$]]|$1|O|3|P|5|Q|7|2F|8|@]|D|@]|E|$R|S]]|$1|T|3|U|5|6|7|2G|8|@]|D|@$9|2H|A|2I|1|2J]]|E|$]]|$1|V|3|W|5|6|7|2K|8|@]|D|@]|E|$]]|$1|X|3|Y|5|Q|7|2L|8|@]|D|@]|E|$R|S]]|$1|Z|3|10|5|6|7|2M|8|@$9|2N|A|2O|B|C]]|D|@]|E|$]]|$1|11|3|12|5|6|7|2P|8|@$9|2Q|A|2R|B|L]]|D|@]|E|$]]|$1|13|3|14|5|6|7|2S|8|@]|D|@$9|2T|A|2U|1|2V]]|E|$]]|$1|15|3|16|5|6|7|2W|8|@$9|2X|A|2Y|B|L]]|D|@]|E|$]]|$1|17|3|18|5|19|7|2Z|8|@]|D|@]|E|$]]|$1|1A|3|-4|5|6|7|30|8|@]|D|@]|E|$]]|$1|1B|3|1C|5|6|7|31|8|@$9|32|A|33|B|L]|$9|34|A|35|B|L]|$9|36|A|37|B|L]|$9|38|A|39|B|L]|$9|3A|A|3B|B|L]]|D|@]|E|$]]|$1|1D|3|-4|5|6|7|3C|8|@]|D|@]|E|$]]|$1|1E|3|1F|5|6|7|3D|8|@$9|3E|A|3F|B|L]]|D|@$9|3G|A|3H|1|3I]]|E|$]]|$1|1G|3|1H|5|6|7|3J|8|@]|D|@]|E|$]]|$1|1I|3|1J|5|6|7|3K|8|@]|D|@$9|3L|A|3M|1|3N]]|E|$]]|$1|1K|3|1L|5|Q|7|3O|8|@]|D|@]|E|$R|S]]|$1|1M|3|1N|5|6|7|3P|8|@]|D|@]|E|$]]|$1|1O|3|1P|5|Q|7|3Q|8|@]|D|@]|E|$R|S]]|$1|1Q|3|-4|5|6|7|3R|8|@]|D|@]|E|$]]]|1R|$1S|$5|1T|1U|1V|E|$1W|1X]]|1Y|$5|1T|1U|1V|E|$1W|1Z]]|20|$5|1T|1U|1V|E|$1W|21]]|22|$5|1T|1U|1V|E|$1W|23]]]]

Important: 
Read the note at the end.

Quick answer : 
Use <code>to_string()</code>. (available since c++11) 
example : 

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

using namespace std;
int main ()
{
 string pi = "pi is " + to_string(3.1415926);
 cout&lt;&lt; "pi = "&lt;&lt; pi &lt;&lt; endl;

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

run it yourself : <a href="http://ideone.com/7ejfaU" rel="noreferrer">http://ideone.com/7ejfaU</a> 
These are available as well : 

<pre><code>string to_string (int val);
string to_string (long val);
string to_string (long long val);
string to_string (unsigned val);
string to_string (unsigned long val);
string to_string (unsigned long long val);
string to_string (float val);
string to_string (double val);
string to_string (long double val);
</code></pre>

Important Note: 
As @Michael Konečný rightfully pointed out, using <code>to_string()</code> is risky at best that is its very likely to cause unexpected results. 
From <a href="http://en.cppreference.com/w/cpp/string/basic_string/to_string" rel="noreferrer">http://en.cppreference.com/w/cpp/string/basic_string/to_string</a> : 

<blockquote>
 With floating point types <code>std::to_string</code> may yield unexpected results as the number of significant digits in the returned string can be zero, see the example. 
 The return value may differ significantly from what <code>std::cout</code> prints by default, see the example.
 <code>std::to_string</code> relies on the current locale for formatting purposes, and therefore concurrent calls to <code>std::to_string</code> from
 multiple threads may result in partial serialization of calls. <code>C++17</code>
 provides <code>std::to_chars</code> as a higher-performance locale-independent
 alternative.
</blockquote>

The best way would be to use <code>stringstream</code> as others such as @dcp demonstrated in <a href="https://stackoverflow.com/a/2125908/2736559">his answer</a>.:

This issue is demonstrated in the following example : 
run the example yourself : <a href="https://www.jdoodle.com/embed/v0/T4k" rel="noreferrer">https://www.jdoodle.com/embed/v0/T4k</a> 

<pre><code>#include &lt;iostream&gt;
#include &lt;sstream&gt;
#include &lt;string&gt;

template &lt; typename Type &gt; std::string to_str (const Type &amp; t)
{
 std::ostringstream os;
 os &lt;&lt; t;
 return os.str ();
}

int main ()
{

 // more info : https://en.cppreference.com/w/cpp/string/basic_string/to_string
 double f = 23.43;
 double f2 = 1e-9;
 double f3 = 1e40;
 double f4 = 1e-40;
 double f5 = 123456789;
 std::string f_str = std::to_string (f);
 std::string f_str2 = std::to_string (f2); // Note: returns "0.000000"
 std::string f_str3 = std::to_string (f3); // Note: Does not return "1e+40".
 std::string f_str4 = std::to_string (f4); // Note: returns "0.000000"
 std::string f_str5 = std::to_string (f5);

 std::cout &lt;&lt; "std::cout: " &lt;&lt; f &lt;&lt; '\n'
 &lt;&lt; "to_string: " &lt;&lt; f_str &lt;&lt; '\n'
 &lt;&lt; "ostringstream: " &lt;&lt; to_str (f) &lt;&lt; "\n\n"
 &lt;&lt; "std::cout: " &lt;&lt; f2 &lt;&lt; '\n'
 &lt;&lt; "to_string: " &lt;&lt; f_str2 &lt;&lt; '\n'
 &lt;&lt; "ostringstream: " &lt;&lt; to_str (f2) &lt;&lt; "\n\n"
 &lt;&lt; "std::cout: " &lt;&lt; f3 &lt;&lt; '\n'
 &lt;&lt; "to_string: " &lt;&lt; f_str3 &lt;&lt; '\n'
 &lt;&lt; "ostringstream: " &lt;&lt; to_str (f3) &lt;&lt; "\n\n"
 &lt;&lt; "std::cout: " &lt;&lt; f4 &lt;&lt; '\n'
 &lt;&lt; "to_string: " &lt;&lt; f_str4 &lt;&lt; '\n'
 &lt;&lt; "ostringstream: " &lt;&lt; to_str (f4) &lt;&lt; "\n\n"
 &lt;&lt; "std::cout: " &lt;&lt; f5 &lt;&lt; '\n'
 &lt;&lt; "to_string: " &lt;&lt; f_str5 &lt;&lt; '\n'
 &lt;&lt; "ostringstream: " &lt;&lt; to_str (f5) &lt;&lt; '\n';

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

output : 

<pre><code>std::cout: 23.43
to_string: 23.430000
ostringstream: 23.43

std::cout: 1e-09
to_string: 0.000000
ostringstream: 1e-09

std::cout: 1e+40
to_string: 10000000000000000303786028427003666890752.000000
ostringstream: 1e+40

std::cout: 1e-40
to_string: 0.000000
ostringstream: 1e-40

std::cout: 1.23457e+08
to_string: 123456789.000000
ostringstream: 1.23457e+08 
</code></pre>

blocks|key|8100|text|您可以在C%2B%2B11中使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|8101|float+val+=+2.5;
std::string+my_val+=+std::to_string(val);|code-block|syntax|javascript|8102|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|$]]

You can use <a href="http://en.cppreference.com/w/cpp/string/basic_string/to_string" rel="nofollow noreferrer">std::to_string</a> in C++11

<pre><code>float val = 2.5;
std::string my_val = std::to_string(val);
</code></pre>

blocks|key|756472|text|一旦您的标准库提供了std::to_chars，就可以使用它：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|756473|std::array<char,+32>+buf;
auto+result+=+std::to_chars(buf.data(),+buf.data()+%2B+buf.size(),+val);
if+(result.ec+==+std::errc())+{
++auto+str+=+std::string(buf.data(),+result.ptr+-+buf.data());
++//+use+the+string
}+else+{
++//+handle+the+error
}|code-block|syntax|javascript|756474|这种方法的优点是：|756475|756476|It是独立于区域设置的，可以防止将数据写入需要'.‘的格式时出现错误。作为小数点|unordered-list-item|756477|，它提供了最短的小数表示，并保证了往返|756478|，它可能比其他标准方法更有效，因为它不使用区域设置，也不需要分配|756479|756480|不幸的是，std::to_string对浮点的效用有限，因为它使用固定的表示法，将小值舍入为零，并为大值生成长字符串，例如|756481|auto+s1+=+std::to_string(1e%2B40);
//+s1+==+10000000000000000303786028427003666890752.000000

auto+s2+=+std::to_string(1e-40);
//+s2+==+0.000000|756482|如果C%2B%2B20标准提案获得批准，std::format可能会获得与std::to_chars相同的更方便的P0645应用编程接口。|756483|entityMap|0|LINK|mutability|MUTABLE|url|https://en.cppreference.com/w/cpp/utility/to_chars|1|http://wg21.link/p0645^0|A|D|A|D|0|0|0|0|0|0|0|0|0|5|E|0|0|G|B|X|D|1H|5|1|0^^$0|@$1|2|3|4|5|6|7|1B|8|@$9|1C|A|1D|B|C]]|D|@$9|1E|A|1F|1|1G]]|E|$]]|$1|F|3|G|5|H|7|1H|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1I|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|1J|8|@]|D|@]|E|$]]|$1|N|3|O|5|P|7|1K|8|@]|D|@]|E|$]]|$1|Q|3|R|5|P|7|1L|8|@]|D|@]|E|$]]|$1|S|3|T|5|P|7|1M|8|@]|D|@]|E|$]]|$1|U|3|-4|5|6|7|1N|8|@]|D|@]|E|$]]|$1|V|3|W|5|6|7|1O|8|@$9|1P|A|1Q|B|C]]|D|@]|E|$]]|$1|X|3|Y|5|H|7|1R|8|@]|D|@]|E|$I|J]]|$1|Z|3|10|5|6|7|1S|8|@$9|1T|A|1U|B|C]|$9|1V|A|1W|B|C]]|D|@$9|1X|A|1Y|1|1Z]]|E|$]]|$1|11|3|-4|5|6|7|20|8|@]|D|@]|E|$]]]|12|$13|$5|14|15|16|E|$17|18]]|19|$5|14|15|16|E|$17|1A]]]]

Use <a href="https://en.cppreference.com/w/cpp/utility/to_chars" rel="nofollow noreferrer"><code>std::to_chars</code></a> once your standard library provides it:

<pre><code>std::array&lt;char, 32&gt; buf;
auto result = std::to_chars(buf.data(), buf.data() + buf.size(), val);
if (result.ec == std::errc()) {
 auto str = std::string(buf.data(), result.ptr - buf.data());
 // use the string
} else {
 // handle the error
}
</code></pre>

The advantages of this method are:

<ul>
<li>It is locale-independent, preventing bugs when writing data into formats such as JSON that require '.' as a decimal point</li>
<li>It provides shortest decimal representation with round trip guarantees</li>
<li>It is potentially more efficient than other standard methods because it doesn't use the locale and doesn't require allocation</li>
</ul>

Unfortunately <code>std::to_string</code> is of limited utility with floating point because it uses the fixed representation, rounding small values to zero and producing long strings for large values, e.g.

<pre><code>auto s1 = std::to_string(1e+40);
// s1 == 10000000000000000303786028427003666890752.000000

auto s2 = std::to_string(1e-40);
// s2 == 0.000000
</code></pre>

C++20 might get a more convenient <code>std::format</code> API with the same benefits as <code>std::to_chars</code> if the <a href="http://wg21.link/p0645" rel="nofollow noreferrer">P0645</a> standards proposal gets approved.

I have a float value that needs to be put into a <code>std::string</code>. How do I convert from float to string?

<pre><code>float val = 2.5;
std::string my_val = val; // error here
</code></pre>

Convert float to std::string 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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我有一个需要放入std::string的浮点值。如何从float转换为string？float val = 2.5;std::string my_val = val; // error here

问在C++中将浮点型转换为std::string
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