blocks|key|789576|text|std::ostringstream|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|789577|示例：|789578|#include+<iostream>
#include+<sstream>+//+for+ostringstream
#include+<string>

int+main()
{
++std::string+name+=+"nemo";
++int+age+=+1000;
++std::ostringstream+out;++
++out+<<+"name:+"+<<+name+<<+",+age:+"+<<+age;
++std::cout+<<+out.str()+<<+'\n';
++return+0;
}|code-block|syntax|javascript|789579|输出：|789580|name:+nemo,+age:+1000|789581|entityMap|0|LINK|mutability|MUTABLE|url|http://en.cppreference.com/w/cpp/io/basic_ostringstream^0|0|I|0|I|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@$9|Z|A|10|B|C]]|D|@$9|11|A|12|1|13]]|E|$]]|$1|F|3|G|5|6|7|14|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|15|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|16|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|17|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|18|8|@]|D|@]|E|$]]]|R|$S|$5|T|U|V|E|$W|X]]]]

<a href="http://en.cppreference.com/w/cpp/io/basic_ostringstream" rel="noreferrer"><code>std::ostringstream</code></a>

Example:

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

int main()
{
 std::string name = "nemo";
 int age = 1000;
 std::ostringstream out; 
 out &lt;&lt; "name: " &lt;&lt; name &lt;&lt; ", age: " &lt;&lt; age;
 std::cout &lt;&lt; out.str() &lt;&lt; '\n';
 return 0;
}
</code></pre>

Output:

<pre><code>name: nemo, age: 1000
</code></pre>

blocks|key|1003690|text|更新，2019年8月：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1003691|看起来C%2B%2B20将会有std::format。参考实现是{fmt}。如果您现在正在寻找printf()替代方案，这将成为新的“标准”方法，值得考虑。|offset|length|style|CODE|1003692|原件：|1003693|使用Boost.Format。它具有printf-like语法、类型安全、std::string结果和许多其他漂亮的东西。你不会回去的。|1003694|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/fmtlib/fmt|1|http://www.boost.org/doc/libs/1_53_0/libs/format/doc/format.html^0|0|B|B|17|8|S|5|0|0|0|I|6|11|B|2|C|1|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|W|8|@$D|X|E|Y|F|G]|$D|Z|E|10|F|G]]|9|@$D|11|E|12|1|13]]|A|$]]|$1|H|3|I|5|6|7|14|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|15|8|@$D|16|E|17|F|G]|$D|18|E|19|F|G]]|9|@$D|1A|E|1B|1|1C]]|A|$]]|$1|L|3|-4|5|6|7|1D|8|@]|9|@]|A|$]]]|M|$N|$5|O|P|Q|A|$R|S]]|T|$5|O|P|Q|A|$R|U]]]]

Update, August 2019:

It looks like C++20 will have <code>std::format</code>. The reference implementation is <a href="https://github.com/fmtlib/fmt" rel="noreferrer">{fmt}</a>. If you are looking for a <code>printf()</code> alternative now, this will become the new "standard" approach and is worth considering.

Original:

Use <a href="http://www.boost.org/doc/libs/1_53_0/libs/format/doc/format.html" rel="noreferrer">Boost.Format</a>. It has <code>printf</code>-like syntax, type safety, <code>std::string</code> results, and lots of other nifty stuff. You won't go back.

blocks|key|789683|text|sprintf在C%2B%2B中工作得很好。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|789684|entityMap|0|LINK|mutability|MUTABLE|url|http://www.cplusplus.com/reference/clibrary/cstdio/sprintf/^0|0|7|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]]]]

<a href="http://www.cplusplus.com/reference/clibrary/cstdio/sprintf/" rel="noreferrer">sprintf</a> works just fine in C++.

blocks|key|1003781|text|这里有一个用于c%2B%2B+sprintf的很好的函数。如果你过多地使用流，它们可能会变得丑陋。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1003782|std::string+string_format(const+std::string+&fmt,+...)+{
++++int+size=100;
++++std::string+str;
++++va_list+ap;

++++while+(1)+{
++++++++str.resize(size);
++++++++va_start(ap,+fmt);
++++++++int+n+=+vsnprintf(&str[0],+size,+fmt.c_str(),+ap);
++++++++va_end(ap);
+++
++++++++if+(n+>+-1+&&+n+<+size)+{
++++++++++++str.resize(n);+//+Make+sure+there+are+no+trailing+zero+char
++++++++++++return+str;
++++++++}
++++++++if+(n+>+-1)
++++++++++++size+=+n+%2B+1;
++++++++else
++++++++++++size+*=+2;
++++}
}|code-block|syntax|javascript|1003783|在C%2B%2B11和更高版本中，std::string保证使用以'\0'结尾的连续存储，因此使用&str[0]将其转换为char+*是合法的。|offset|length|style|CODE|1003784|有人指出，可变参数不应该遵循按引用传递，并且如果没有必要，c%2B%2B不复制字符串是很好的。在这种情况下，这会修复它。|1003785|std::string+string_format(std::string+fmt,+...)+{|1003786|entityMap^0|0|0|T|4|19|7|1L|6|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@$I|V|J|W|K|L]|$I|X|J|Y|K|L]|$I|Z|J|10|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|11|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|Q|3|-4|5|6|7|13|8|@]|9|@]|A|$]]]|R|$]]

Here's a nice function for a c++ sprintf. Streams can get ugly if you use them too heavily.
<pre><code>std::string string_format(const std::string &amp;fmt, ...) {
 int size=100;
 std::string str;
 va_list ap;

 while (1) {
 str.resize(size);
 va_start(ap, fmt);
 int n = vsnprintf(&amp;str[0], size, fmt.c_str(), ap);
 va_end(ap);
 
 if (n &gt; -1 &amp;&amp; n &lt; size) {
 str.resize(n); // Make sure there are no trailing zero char
 return str;
 }
 if (n &gt; -1)
 size = n + 1;
 else
 size *= 2;
 }
}
</code></pre>
In C++11 and later, std::string is guaranteed to use contiguous storage that ends with <code>'\0'</code>, so it is legal to cast it to <code>char *</code> using <code>&amp;str[0]</code>.
It has been pointed out that variadic arguments are not supposed to follow pass-by-reference, and c++ is good about not copying strings if it doesn't have to. In that case, this fixes it.
<pre><code>std::string string_format(std::string fmt, ...) {
</code></pre>

blocks|key|789891|text|您可以使用iomanip头文件来格式化输出流。检查this！|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|789892|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/25120551/463414^0|P|4|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]]]]

You can use iomanip header file to format the output stream.
Check <a href="https://stackoverflow.com/a/25120551/463414">this</a>!

blocks|key|789928|text|根据您对sprintf()ing的具体计划，std::to_string()可能比其他选项更有用、更常用：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|789929|void+say(const+std::string&+message)+{
+//+...
}

int+main()+{
++say(std::to_string(5));
++say("Which+is+to+say+"+%2B+std::to_string(5)+%2B+"+words");
}|code-block|syntax|javascript|789930|std::to_string()的主要优点是，它可以很容易地扩展，以支持sprintf()甚至想不到的附加类型--有点像Java的Object.toString()方法。|789931|entityMap^0|4|9|M|G|0|0|0|G|10|9|1T|H|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|N|$]]

Depending on what exactly you plan on <code>sprintf()</code>ing, <code>std::to_string()</code> might be useful and more idiomatic than other options:

<pre class="lang-cpp prettyprint-override"><code>void say(const std::string&amp; message) {
 // ...
}

int main() {
 say(std::to_string(5));
 say("Which is to say " + std::to_string(5) + " words");
}
</code></pre>

The main advantage of <code>std::to_string()</code>, IMHO, is that it can be extended easily to support additional types that <code>sprintf()</code> can't even dream of stringifying - kind of like Java's <code>Object.toString()</code> method.

blocks|key|789629|text|使用字符串流可以达到同样的效果。此外，您可以包含<cstdio>，但仍然使用snprintf。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|789630|entityMap^0|O|8|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

Use a stringstream to achieve the same effect. Also, you can include <code>&lt;cstdio&gt;</code> and still use snprintf.

I know that <code>std::cout</code> is the C++ equivalent of <code>printf</code>.

What is the C++ equivalent of <code>sprintf</code>?

C++ equivalent of sprintf?

我知道std::cout是C++版的printf。sprintf的C++等价物是什么

问sprintf的C++等价物？
EN

回答 7

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