blocks|key|1659027|text|ASCII字符7是贝尔字符，它在C中表示为\a。当这个字符在终端上输出时，一些终端会发出蜂鸣声；现在，很多终端都不会发出蜂鸣声。(我看着你呢，Ubuntu。)|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1659028|entityMap^0|L|2|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|$]]

ASCII character 7 is the BELL character, and it's represented in C as <code>\a</code>. Some terminals will produce a beep when this character is output on the terminal; nowadays, many don't. (I'm looking at you, Ubuntu.)

blocks|key|2077617|text|回到黑暗的时代，ASCII是从BAUDOT的骨灰中编写出来的，terminal是一大块铁，它把墨水敲击在纸上，通常包括一个纸带打孔机和阅读器，并通过旋转的轮子和继电器来解释击键以产生几百波特的异步串行信号。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2077618|如果操作员在它敲打文本的舒缓噪音中睡着了，它有一个实际的铃声，它可以敲响。八进制字符007、十六进制字符0x07或C字符或字符串常量中的\a字符在收到时会发出响铃。|style|CODE|2077619|随着终端变得更小，并且只有很少或没有活动部件，物理铃声被蜂鸣器取代。|2077620|当被要求显示控制字符时，终端仿真器(在Windows、xterm或Unix中也称为控制台窗口)究竟执行什么操作目前还没有很好地标准化。它应该发出响声或闪光窗户，但你的里程数会有所不同。|2077621|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/ASCII|1|http://en.wikipedia.org/wiki/Baudot_code|2|http://en.wikipedia.org/wiki/ASR-33_Teletype^0|8|5|0|F|6|1|V|8|2|0|1W|2|0|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@$A|Y|B|Z|1|10]|$A|11|B|12|1|13]|$A|14|B|15|1|16]]|C|$]]|$1|D|3|E|5|6|7|17|8|@$A|18|B|19|F|G]]|9|@]|C|$]]|$1|H|3|I|5|6|7|1A|8|@]|9|@]|C|$]]|$1|J|3|K|5|6|7|1B|8|@]|9|@]|C|$]]|$1|L|3|-4|5|6|7|1C|8|@]|9|@]|C|$]]]|M|$N|$5|O|P|Q|C|$R|S]]|T|$5|O|P|Q|C|$R|U]]|V|$5|O|P|Q|C|$R|W]]]]

Back in the dark ages when <a href="http://en.wikipedia.org/wiki/ASCII" rel="noreferrer">ASCII</a> was codified out of the ashes of <a href="http://en.wikipedia.org/wiki/Baudot_code" rel="noreferrer">BAUDOT</a>, a <a href="http://en.wikipedia.org/wiki/ASR-33_Teletype" rel="noreferrer">terminal</a> was a large chunk of iron that hammered ink onto paper, often included a paper tape punch and reader, and interpreted keystrokes to generate an asynchronous serial signal at a few hundred baud with spinning wheels and relays.

In case an operator fell asleep to the soothing noises of it hammering out text, it had an actual bell it could ring. The character coded 007 in octal, 0x07 in hex, or as <code>\a</code> in a C character or string constant rang the bell when received.

As terminals became smaller and implemented with few or no moving parts, the physical bell was replaced by a beeper.

Exactly what your terminal emulator (aka a Console Window in Windows, xterm or something similar in Unix) does when it is asked to display that control character is not well standardized today. It ought to make a noise or flash the window, but your mileage will vary.

blocks|key|1659017|text|看看这个维基百科词条：bell+character|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1659018|在C编程语言(创建于1972年)中，钟形字符可以用\a放在字符串或字符常量中('a‘代表"alert“或"audible”，之所以选择它，是因为\b已经用作退格键)。|1659019|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/Bell_character^0|B|E|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]]|C|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]]]

Have a look at this wikipedia entry: <a href="http://en.wikipedia.org/wiki/Bell_character" rel="noreferrer">bell character</a>:

In the C Programming Language (created in 1972), the bell character can be placed in a string or character constant with \a ('a' stands for "alert" or "audible" and was chosen because \b was already used for backspace).

blocks|key|5605392|text|您将听到PC内置扬声器发出的嘟嘟声(而不是您可能连接的外置扬声器或耳机)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5605393|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|$]]

You'll hear a beep from your PC's internal speaker (not the external speakers or headphones you may have attached).

blocks|key|5605431|text|事实上，\a确实触发了系统钟声。这是ASCII+BEL字符的转义序列。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5605432|entityMap^0|4|2|O|3|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

<code>\a</code> does in fact trigger the system chime. It's the escape sequence for the ASCII <code>BEL</code> character.

blocks|key|2077664|text|除了你已经得到的所有答案之外，考虑到你的程序可能不会编译。修复后的版本如下：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2077665|#include+<stdio.h>
#include+<stdlib.h>

int+main()
{
++++printf("\a");
++++return+EXIT_SUCCESS;
}|code-block|syntax|javascript|2077666|最重要的变化是系统头必须加上<和>，而不是引号。而且，最好知道main()函数总是返回一个int+(给操作系统)，并且这个int编码在头文件stdlib.h中的两个常量EXIT_SUCCESS和EXIT_FAILURE中。|2077667|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|$]]

Apart from all the answers you've got, take into account that your program won't probably compile. Here is the fixed version:

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

int main()
{
 printf("\a");
 return EXIT_SUCCESS;
}
</code></pre>

The most important change is that system headers must be surronded with &lt; and >, instead of quotes. Also, it is better to know that the main() function always returns an int (to the operating system), and that this int is coded in two constants, EXIT_SUCCESS, and EXIT_FAILURE, in the header stdlib.h

blocks|key|4188021|text|字符串可以包含处理方式与所有其他字符不同的字符。最常显式使用的是'\n'。'\n'字符不会在控制台中打印字符，而是告诉控制台开始一个新行。这种特殊字符被称为不可打印字符，因为它们在c中没有自己的可见表示形式，必须使用转义序列来代替。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4188022|在转义序列"\a"中，a前面的反斜杠告诉编译器a是一个特殊字符的标识符，将存储它的字符值，而不是'a'的字符值。|4188023|'\a'转义序列是可以听到的钟形字符，通过print()将该字符提供给控制台应该会发出蜂鸣声。某些控制台不发出蜂鸣音。|4188024|以下是some特殊字符，链接来自c%2B%2B引用，但大多数应该对c有效。|4188025|entityMap|0|LINK|mutability|MUTABLE|url|http://www.cppreference.com/wiki/escape_sequences^0|W|4|11|4|0|5|4|1C|3|0|0|4|0|3|4|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@$9|U|A|V|B|C]|$9|W|A|X|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Y|8|@$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|13|8|@$9|14|A|15|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|16|8|@]|D|@$9|17|A|18|1|19]]|E|$]]|$1|L|3|-4|5|6|7|1A|8|@]|D|@]|E|$]]]|M|$N|$5|O|P|Q|E|$R|S]]]]

Strings can contain characters which are handled different from all the other characters. The most often explicit used one is <code>'\n'</code>. The <code>'\n'</code> character does not print a character in the console, instead it tells the console to start a new line. Such special characters are called non printable since they have no own visible representation in c and have to use escape sequences instead.

In the escape sequence <code>"\a"</code> the backslash before the a tells the compiler that the a is an identifier for a special character and will store its char-value instead of the char-value of <code>'a'</code>.

The <code>'\a'</code> escape sequence is the audible bell character, giving this character to a console via print() should cause a beep sound. Some consoles wont beep.

Here are <a href="http://www.cppreference.com/wiki/escape_sequences" rel="nofollow noreferrer">some</a> special characters, the link is from a c++ reference but most should be valid for c.

blocks|key|2077583|text|\a是ASCII声音警报(“铃声”)控制字符的C表示。在一个老式的串行终端上，输出该字符会产生“嘟嘟声”。您的终端仿真器可能实现也可能不实现此功能。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2077584|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|$]]

\a is the C representation of the ASCII audible alert ("bell") control character.
On an old-school serial terminal, outputting that character produced a "beep" sound. Your terminal emulator may or may not implement this feature.

blocks|key|1659088|text|试试更简单的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1659089|printf("hello\tworld");
printf("hello\nworld");|code-block|syntax|javascript|1659090|看看会发生什么。|1659091|正如其他人所指出的，您使用BELL+char的示例可能不会在今天的烤面包机%5EH%5EH计算机上工作；大多数终端重定向'bell‘字符以丢弃或短暂地闪现终端。|1659092|相信我，您希望在夜间编码过程中保持这种状态:)|1659093|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Try something simpler:

<pre><code>printf("hello\tworld");
printf("hello\nworld");
</code></pre>

and see what happens. 

Your example with the BELL char, as others have pointed out, probably won't work on today's toasters^H^H^H^H^H^H^H^H computers; most terminals redirect the 'bell' character to either be discarded or to flash the terminal briefly. 

And believe me, you want to keep it that way for the night-coding sessions :)

blocks|key|4188054|text|上面的程序是你写的，我已经在代码块中用GNU的GCC编译器试过了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4188055|它工作得很好..|4188056|如果你想听到蜂鸣声，你可以尝试另一种方式，它将只在Windows中有用！|4188057|#include<stdio.h>
#include<windows.h>
main()
{
+++Beep(600,600);+/*+you+have+to+enter+both+the+values+whatever+you+want
}|code-block|syntax|javascript|4188058|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

The above program which you have written I have tried it in the code blocks using GNU GCC Compiler..

It was working fine..

If you want to hear a beep sound you can try it another way it will only be useful in Windows!

<pre><code>#include&lt;stdio.h&gt;
#include&lt;windows.h&gt;
main()
{
 Beep(600,600); /* you have to enter both the values whatever you want
}
</code></pre>

blocks|key|2077772|text|有趣的是，这似乎适用于所有没有wWinMain或WinMain入口点的构建。wprintf(L"\a")听起来很适合构建Unicode。(这里是Win+7)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2077773|PC扬声器过去依赖于"speaker.drv“，但这一小小的美丽已经被一段时间过去了，取而代之的是现在移动到user+mode+system+sounds+agent中的beep.sys。|2077774|从命令提示符启用和禁用扬声器也会在here中讨论。|2077775|entityMap|0|LINK|mutability|MUTABLE|url|https://blogs.msdn.microsoft.com/larryosterman/2010/01/04/whats-up-with-the-beep-driver-in-windows-7/|1|https://superuser.com/questions/227939/how-to-make-the-pc-speaker-beep-from-the-windows-7-command-prompt^0|12|E|0|1I|T|0|0|H|4|1|0^^$0|@$1|2|3|4|5|6|7|T|8|@$9|U|A|V|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|W|8|@]|D|@$9|X|A|Y|1|Z]]|E|$]]|$1|H|3|I|5|6|7|10|8|@]|D|@$9|11|A|12|1|13]]|E|$]]|$1|J|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|K|$L|$5|M|N|O|E|$P|Q]]|R|$5|M|N|O|E|$P|S]]]]

As a matter of interest this appears to work in all builds that don't have a wWinMain or WinMain entry point. <code>wprintf(L"\a")</code> sounds fine for Unicode builds. (Win 7 here).

The PC speaker used to depend on "speaker.drv" but that little beauty has been taken away some time back and replaced with beep.sys which is now moved into the <a href="https://blogs.msdn.microsoft.com/larryosterman/2010/01/04/whats-up-with-the-beep-driver-in-windows-7/" rel="nofollow noreferrer">user mode system sounds agent</a>. 

Enabling and disabling the speaker from the command prompt is also discussed <a href="https://superuser.com/questions/227939/how-to-make-the-pc-speaker-beep-from-the-windows-7-command-prompt">here</a>.

blocks|key|2077784|text|#include<stdio.h>
int+main()
{

++++int+i+=+263;
++++putchar(i);++//+or+you+can+directly+use+putchar(263);
++++return+0;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|2077785|当你在输出屏幕上时，这个程序会产生一个铃声|unstyled|2077786|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>#include&lt;stdio.h&gt;
int main()
{

 int i = 263;
 putchar(i); // or you can directly use putchar(263);
 return 0;
}
</code></pre>

This program produces a bell sound while you are on the output screen

blocks|key|4188134|text|问题不在于你的C程序是否编译它，而完全取决于你的终端设置。在UEFI出现之前，它们通常会用笔记本电脑和个人电脑附带的PC扬声器发出蜂鸣声|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4188135|https://en.wikipedia.org/wiki/PC_speaker|offset|length|4188136|我用两台笔记本电脑测试了一下，其中一台是在UEFI之前买的，甚至有一台是在UEFI之后买的，另一台是UEFI之后买的|4188137|我在两个测试(都是加载了pcspkr模块的linux系统)上运行echo+-e+'\a'，并确保UEFI存在之前的笔记本电脑发出蜂鸣声，其他笔记本电脑只是静默不响。|style|CODE|4188138|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|14|0|0|0|C|6|W|C|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@$D|U|E|V|1|W]]|A|$]]|$1|F|3|G|5|6|7|X|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|Y|8|@$D|Z|E|10|J|K]|$D|11|E|12|J|K]]|9|@]|A|$]]|$1|L|3|-4|5|6|7|13|8|@]|9|@]|A|$]]]|M|$N|$5|O|P|Q|A|$R|C]]]]

the problem isnt about wheter your C program compiles its fully depend your terminal settings usually they make beeps using PC speakers that comes with laptop and PCs before UEFI exist
<a href="https://en.wikipedia.org/wiki/PC_speaker" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/PC_speaker</a>
i tested it using 2 laptops one of them were bought before UEFI even a thing and other bought after UEFI become common thing
i run <code>echo -e '\a'</code> on both test (both linux system with <code>pcspkr</code> module loaded) and sure the laptop before UEFI exist is beep other laptop just silent

I'm a brand-new student in programming arena so I can't grasp this program written in my book that I have been following for a few days. The program is like this:

<pre><code>#include "stdio.h"

main()
{
 printf("\a");
}
</code></pre>

What does this program mean? Does this program mean that we could hear a ringing bell? I can't hear any ringing bell sound!!!

This program sounds the bell!

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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我是一个全新的编程领域的学生，所以我不能掌握我的书中写的这个程序，我已经关注了几天。程序是这样的：#include "stdio.h"main(){ printf("\a");}这个程序是什么意思？这个节目是不是意味着我们能听到铃声？我听不到任何铃声！

问这个程序敲响了铃声！
EN

回答 13

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问这个程序敲响了铃声！EN

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问这个程序敲响了铃声！
EN