blocks|key|3791135|text|是的，你可以直接调用这个函数，但是你这样做的理由是有缺陷的。与执行实际功能所用的时间相比，通过省去对操作员的子例程调用而节省的时间可以忽略不计；这就像是在活动车顶关闭时关闭车窗，以减少降雨。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3791136|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Yes you could call the function directly, however your reasoning to do so is flawed. The time you save by eliminating the subroutine call to the operator is negligible when compared to the time taken to perform the actual function; this would be like closing the windows of your car while the convertible roof is down in order to reduce the rain.

blocks|key|442402|text|进行函数调用所需的时间比打印字符串所需的时间要短得多。您可以(通常也应该)忽略使用您的方法可以节省的时间。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|442403|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

The time required to make a function call is much, much smaller than the amount of time it takes to print your string. The amount of time you might save with your approach can (and usually should) be ignored.

blocks|key|442456|text|您可以直接使用系统调用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|442457|http://docs.cs.up.ac.za/programming/asm/derick_tut/syscalls.html|offset|length|442458|例如，本页解释了linux系统调用。您可以从我复制的链接开始，使用汇编使用许多方法，或者换句话说，在不调用它的函数的情况下做一些事情。|442459|但我猜那是一个刁钻的问题，如果我有一家公司，我永远不会雇佣一个使用系统调用而不是函数的人。|442460|这是将sys_write(4)与标准输出(1)一起使用的示例。您可以将汇编代码内联到C/C%2B%2B代码中。http://docs.cs.up.ac.za/programming/asm/derick_tut/#helloworld|442461|entityMap|0|LINK|mutability|MUTABLE|url|1|http://docs.cs.up.ac.za/programming/asm/derick_tut/#helloworld^0|0|0|1S|0|0|0|0|1F|1Q|1|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@$D|W|E|X|1|Y]]|A|$]]|$1|F|3|G|5|6|7|Z|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|10|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|11|8|@]|9|@$D|12|E|13|1|14]]|A|$]]|$1|L|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|M|$N|$5|O|P|Q|A|$R|C]]|S|$5|O|P|Q|A|$R|T]]]]

You can directly use system calls.

<a href="http://docs.cs.up.ac.za/programming/asm/derick_tut/syscalls.html" rel="nofollow">http://docs.cs.up.ac.za/programming/asm/derick_tut/syscalls.html</a>

This page, for example, explains linux system calls. You can start from the link I copied, and use many methods using assembly, or to say it in the other way, do something without calling the function of it.

But I'm guessing that was a trick question and if I had a company, I would never hire a person that uses system calls instead of functions.

This is an example of using sys_write(4) with standart output(1). You can inline assembly codes into your C/C++ code.
<a href="http://docs.cs.up.ac.za/programming/asm/derick_tut/#helloworld" rel="nofollow">http://docs.cs.up.ac.za/programming/asm/derick_tut/#helloworld</a>

blocks|key|442501|text|如果希望在所有符合标准的C%2B%2B实现之间具有可移植性，可以通过以下方式将字符串打印到标准输出|type|unstyled|depth|inlineStyleRanges|entityRanges|data|442502|const+char+*+str+=+"Hello+World\n";
fprintf(stdout,+str);
fputs(str,+stdout);
for+(int+i=0;+str[i]!=0;+%2B%2Bi)
++++putchar(str[i]);
for+(int+i=0;+str[i]!=0;+%2B%2Bi)
++++putc(str[i],+stdout);
for+(int+i=0;+str[i]!=0;+%2B%2Bi)
++++fputc(str[i],+stdout);
fwrite(str,+sizeof(*str),+strlen(str),+stdout);|code-block|syntax|javascript|442503|此外，您还可以使用std::cerr和std::clog。它们写入stderr而不是stdout，但从用户的角度来看，这通常是相同的位置：|offset|length|style|CODE|442504|std::cerr+<<+str;
std::clog+<<+str;|442505|从效率的角度来看，我怀疑这些都不会对你有帮助。为此，您可能希望查看更多特定于平台的内容。对于POSIX系统，请参阅Dave+S给出的答案。对于Windows，请参阅this+link。|442506|你不应该做的是打开你的头文件并模仿他们使用的东西。至少，不是在中间层，他们在自己的实现中使用不同的各种晦涩的函数。在下一个版本中，这些函数可能不存在。然而，如果你深入到最深的层次，你会发现特定于操作系统的调用，就像我在上面提供的链接中那样。只要你停留在相同的操作系统上，甚至在不同的操作系统版本之间，使用这些软件应该是安全的。|442507|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/13689312/440119|1|http://msdn.microsoft.com/en-us/library/windows/desktop/ms683497%2528v=vs.85%2529.aspx^0|0|0|9|9|J|9|X|6|16|6|0|0|1L|6|0|2A|9|1|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|14|8|@$I|15|J|16|K|L]|$I|17|J|18|K|L]|$I|19|J|1A|K|L]|$I|1B|J|1C|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|1D|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|1E|8|@]|9|@$I|1F|J|1G|1|1H]|$I|1I|J|1J|1|1K]]|A|$]]|$1|Q|3|R|5|6|7|1L|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1M|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]|10|$5|V|W|X|A|$Y|11]]]]

If you want portability across all standards compliant C++ implementations, you can print a string to standard output in the following ways

<pre><code>const char * str = "Hello World\n";
fprintf(stdout, str);
fputs(str, stdout);
for (int i=0; str[i]!=0; ++i)
 putchar(str[i]);
for (int i=0; str[i]!=0; ++i)
 putc(str[i], stdout);
for (int i=0; str[i]!=0; ++i)
 fputc(str[i], stdout);
fwrite(str, sizeof(*str), strlen(str), stdout);
</code></pre>

Additionally, you can use <code>std::cerr</code> and <code>std::clog</code>. They write to <code>stderr</code> instead of <code>stdout</code>, but from the user's perspective, that's often the same place:

<pre><code>std::cerr &lt;&lt; str;
std::clog &lt;&lt; str;
</code></pre>

From an efficiency perspective, I doubt any of these are going to help you. For that purpose, you might want to look at something a bit more platform specific. For POSIX systems, see the answer given by <a href="https://stackoverflow.com/a/13689312/440119">Dave S</a>. For Windows, see <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/ms683497%28v=vs.85%29.aspx" rel="nofollow noreferrer">this link</a>.

What you shouldn't do, is open up your header files and imitate what they use. At least, not at the middle levels, where they are using different various obscure functions within their own implementation. Those functions might not exist upon the next release. However, if you go to the deepest levels, you will find OS specific calls like the ones in the link I provided above. Those should be safe to use as long as you stay on the same OS, or even between OS versions.

blocks|key|3791275|text|在UNIX类型的系统上，您可以执行以下操作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3791276|#include+<unistd.h>
#include+<stdio.h>

int+main()
++{
++const+char+x[]+=+"Hello+World!";
++write(STDOUT_FILENO,+x,+strlen(x));+//+Feel+free+to+check+the+return+value.
++return+0;
++}|code-block|syntax|javascript|3791277|我很好奇你这样做的动机是什么。在信号处理程序之外，我不愿意像这样进入较低级别的调用。I/O的性能将是时间的主要驱动因素，而不是通常经过大量优化/内联的中间函数调用。|3791278|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|$]]

On a UNIX type system, you can do the following.

<pre><code>#include &lt;unistd.h&gt;
#include &lt;stdio.h&gt;

int main()
 {
 const char x[] = "Hello World!";
 write(STDOUT_FILENO, x, strlen(x)); // Feel free to check the return value.
 return 0;
 }
</code></pre>

I'm curious what your motivation for doing this would be. Outside of signal handlers, I'm reluctant to go to the lower level calls like this. The performance of the I/O will be the primary driver of time, not the intermediate function calls which are usually fairly heavily optimized / inlined.

I had learned that 

<pre><code>inline ostream &amp; _Cdecl ostream::operator&lt;&lt; (const signed char * _s) {
 outstr(_s, (const signed char *)0);
 return *this;
}
</code></pre>

is how the insertion operator (&lt;&lt;) is declared(overloaded) in the iostream.h header file. Can I possibly use the same function to print a string value on screen?

I tried

<pre><code>#include&lt;iostream.h&gt;
int main() {
 outstr("Hello world!", (const signed char *)0);
 return 0;
}
</code></pre>

it ended up in error. I would like to use something like this in order to see if there is some possible way to answer this query of printing something on screen without using printf, cout or puts().

Update: I would welcome if you have any suggestions other than

<pre><code>#include&lt;stdlib.h&gt;
void main() {
 system("echo /"Hello world!/"");
}
</code></pre>

NB: I have no restrictions if you can provide the C equivalent code that can print without a printf(), cout or puts()

To print something without using cout, printf or puts()

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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我学到了inline ostream & _Cdecl ostream::operator<< (const signed char * _s) { outstr(_s, (const signed char *)0); return *this;}是在iostream.h头文件中声明(重载)插入运算符(<...

问不使用cout、printf或put()打印内容
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