blocks|key|386354|text|字符数组中缺少一个空终止符。试着把它变成5个字符，最后一个字符“\0”。这让程序知道您的字符串已经完成，而不需要知道大小。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|386355|什么是以空结尾的字符串？|offset|length|386356|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/2037209/what-is-a-null-terminated-string^0|0|0|C|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

You are missing a null terminator on your character array. Try making it 5 characters and making the last character '\0'. This lets the program know that your string is done without needing to know the size.

<a href="https://stackoverflow.com/questions/2037209/what-is-a-null-terminated-string">What is a null-terminated string?</a>

blocks|key|402922|text|请参阅istream的文档：：；它没有附加空终止符，而是告诉它读取准确的4个字符。正如其他人所指出的，<<操作符正在寻找一个空终止符，因此它将继续读取数组的末尾，直到找到一个。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|402923|我同意使用std::string而不是char[]的另一个建议。|402924|entityMap|0|LINK|mutability|MUTABLE|url|http://www.cplusplus.com/reference/istream/istream/read/^0|1F|2|3|C|0|0|5|B|J|6|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@$9|S|A|T|1|U]]|E|$]]|$1|F|3|G|5|6|7|V|8|@$9|W|A|X|B|C]|$9|Y|A|Z|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|10|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

See <a href="http://www.cplusplus.com/reference/istream/istream/read/" rel="nofollow">the documentation for istream::read</a>; it doesn't append a null terminator, and you're telling it to read exactly 4 characters. As others have indicated, the <code>&lt;&lt;</code> operator is looking for a null terminator so it's continuing to read past the end of the array until it finds one.

I concur with the other suggested answer of using <code>std::string</code> instead of <code>char[]</code>.

blocks|key|402970|text|operator<<+for+std::ostream+for+char+const*+期望以空结尾的字符串的重载。你给它一个4个字符的数组。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|402971|改用标准库string类：|402972|std::string+dataLabel;|code-block|syntax|javascript|402973|entityMap|0|LINK|mutability|MUTABLE|url|http://en.cppreference.com/w/cpp/io/basic_ostream/operator_ltlt2^0|0|A|F|C|W|B|18|A|0|0|5|6|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@$9|11|A|12|1|13]]|E|$]]|$1|F|3|G|5|6|7|14|8|@$9|15|A|16|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|17|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|18|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

The overload of <code>operator&lt;&lt;</code> for <code>std::ostream</code> for <code>char const*</code> <a href="http://en.cppreference.com/w/cpp/io/basic_ostream/operator_ltlt2" rel="nofollow">expects a null terminated string</a>. You are giving it an array of 4 characters.

Use the standard library <code>string</code> class instead:

<pre><code>std::string dataLabel;
</code></pre>

blocks|key|403047|text|您的char[]数组不是以空结尾的，但是接受char*输入的<<操作符需要一个空终止符。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|403048|char+dataLabel[5];
wav.read(dataLabel,+4);+//Read+data+label
dataLabel[4]+=+0;
cout+<<+"Data+label:"+<<+dataLabel+<<++"\n";|code-block|syntax|javascript|403049|entityMap^0|2|6|M|5|U|2|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$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]]|$1|K|3|-4|5|6|7|U|8|@]|D|@]|E|$]]]|L|$]]

Your <code>char[]</code> array is not null-terminated, but the <code>&lt;&lt;</code> operator that accepts <code>char*</code> input requires a null terminator.

<pre><code>char dataLabel[5];
wav.read(dataLabel, 4); //Read data label
dataLabel[4] = 0;
cout &lt;&lt; "Data label:" &lt;&lt; dataLabel &lt;&lt; "\n";
</code></pre>

blocks|key|386464|text|变量dataLabel的定义如下|type|unstyled|depth|inlineStyleRanges|entityRanges|data|386465|char[4]+dataLabel;|code-block|syntax|javascript|386466|只有四个字符在语句中填充了{+'d'，'a'，'t'，'a‘)|386467|wav.read(dataLabel,+sizeof(dataLabel));//|386468|因此，当该字符数组的参数是字符数组时，该字符数组不具有operator+<<所需的终止零。|offset|length|style|CODE|386469|因此，在本声明中|386470|cout+<<+"Data+label:"+<<dataLabel+<<++"\n";|386471|这个程序有未定义的行为。|386472|把它改成|386473|std::cout+<<+"Data+label:+";
std::cout.write(+dataLabel,+sizeof(+dataLabel+)+)++<<++"\n";|386474|entityMap^0|0|0|0|0|R|B|0|0|0|0|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]]|$1|G|3|H|5|6|7|14|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|16|8|@$M|17|N|18|O|P]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|19|8|@]|9|@]|A|$]]|$1|S|3|T|5|D|7|1A|8|@]|9|@]|A|$E|F]]|$1|U|3|V|5|6|7|1B|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1C|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|D|7|1D|8|@]|9|@]|A|$E|F]]|$1|10|3|-4|5|6|7|1E|8|@]|9|@]|A|$]]]|11|$]]

Variable dataLabel is defined like

<pre><code>char[4] dataLabel;
</code></pre>

that it has only four characters that were filled with characters { 'd', 'a', 't', 'a' ) in statement

<pre><code>wav.read(dataLabel, sizeof(dataLabel));//
</code></pre>

So this character array does not have the terminating zero that is required for the <code>operator &lt;&lt;</code> when its argument is a character array. 

Thus in this statement 

<pre><code>cout &lt;&lt; "Data label:" &lt;&lt;dataLabel &lt;&lt; "\n";
</code></pre>

the program has undefined behaviour.

Change it to

<pre><code>std::cout &lt;&lt; "Data label: ";
std::cout.write( dataLabel, sizeof( dataLabel ) ) &lt;&lt; "\n";
</code></pre>

I have a <code>char[4] dataLabel</code> that when I say 

<pre><code>wav.read(dataLabel, sizeof(dataLabel));//Read data label
cout &lt;&lt; "Data label:" &lt;&lt;dataLabel &lt;&lt; "\n";
</code></pre>

I get the output <code>Data label:data�</code> but when I loop through each char I get the correct output, which should be "data".

<pre><code>for (int i = 0; i &lt; sizeof(dataLabel); ++i) {
 cout &lt;&lt; "Data label " &lt;&lt; i &lt;&lt; " " &lt;&lt; dataLabel[i] &lt;&lt; "\n";
}
</code></pre>

The sizeof returns 4. I'm at a loss for what the issue is. 

EDIT: What confuses me more is that essentially the same code from earlier in my program works perfectly. 

<pre><code>ifstream wav;
wav.open("../../Desktop/hello.wav", ios::binary);
char riff[4]; //Char to hold RIFF header

if (wav.is_open()) {
 wav.read(riff, sizeof(riff));//Read RIFF header
 if ((strcmp(riff, "RIFF"))!=0) { 
 fprintf(stderr, "Not a wav file");
 exit(1);
 }
 else {
 cout &lt;&lt; "RIFF:" &lt;&lt; riff &lt;&lt; "\n";
</code></pre>

This prints <code>RIFF:RIFF</code> as intended.

Extra characters on cstring when cout

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

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

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

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

我有一个char[4] dataLabel当我说wav.read(dataLabel, sizeof(dataLabel));//Read data labelcout << "Data label:" <<dataLabel << "\n";我得到了输出Data label:data�，但是当我循环遍历每个字符时，...

问cout时cstring上的额外字符
EN

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cout时cstring上的额外字符EN

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cout时cstring上的额外字符
EN