C ++字符串文字转义字符 [英] C++ string literals escape character

问题描述

字符串文字中的转义字符 \ 有什么规则？是否有转义的所有字符的列表？特别是，当我在gedit的字符串文字中使用 \ ，并且跟随它由任何三个数字，它们不同地给它们上色。我试图创建一个 std :: string 从字符构造的字符 0 后跟空字符 \0 ），后跟字符 0 。但是，语法高亮提醒我，也许这将创建一个像 0 后跟空字符（ \00 ，aka \0 ），也就是说，只有两个字符。

只是这一个问题，是这个最好的方法：

  std :: string（0\0 0，3）//字符串连接
  

字符串字面量一般？例如

解决方案

控制字符：

（十六进制代码假定与ASCII兼容的字符编码。）

• \a = \x07 = alert（bell）


• \b = \x08 = backspace


• \t = \x09 =水平标签


• \\\
= \x0A =换行符（或换行符）


• \v = \x0B =垂直标签


• \f = \x0C =表单Feed


• \r = \x0D =回车


• \e = \x1B = escape（非标准GCC扩展）

标点符号：

• \ =引号''）


• \' = apostrophe '）


• \？ =问号以避免三字母）


• 
  
• \\ =反斜杠

数字字符引用：

• \ +最多3个八进制数字


• \x +任意多个十六进制数字


• \u + 4个十六进制数字（Unicode BMP，C ++ 11中的新增）


• \U + 8个十六进制数字（Unicode astral planes，new in C ++ 11）

\0 = \00 = \000 =空字符的八进制表达式

如果你想在 \0 然后是，我建议字符串连接。注意，字面之间的空格是可选的，所以你可以写\00。

What are the rules for the escape character \ in string literals? Is there a list of all the characters that are escaped? In particular, when I use \ in a string literal in gedit, and follow it by any three numbers, it colors them differently. I was trying to create a std::string constructed from a literal with the character 0 followed by the null character (\0), followed by the character 0. However, the syntax highlighting alerted me that maybe this would create something like the character 0 followed by the null character (\00, aka \0), which is to say, only two characters.

For the solution to just this one problem, is this the best way to do it:

std::string ("0\0" "0", 3)  // String concatenation 

And is there some reference for what the escape character does in string literals in general? What is '\a', for instance?

解决方案

Control characters:

(Hex codes assume an ASCII-compatible character encoding.)

• \a = \x07 = alert (bell)
• \b = \x08 = backspace
• \t = \x09 = horizonal tab
• \n = \x0A = newline (or line feed)
• \v = \x0B = vertical tab
• \f = \x0C = form feed
• \r = \x0D = carriage return
• \e = \x1B = escape (non-standard GCC extension)

Punctuation characters:

• \" = quotation mark (backslash not required for '"')
• \' = apostrophe (backslash not required for "'")
• \? = question mark (used to avoid trigraphs)
• \\ = backslash

Numeric character references:

• \ + up to 3 octal digits
• \x + any number of hex digits
• \u + 4 hex digits (Unicode BMP, new in C++11)
• \U + 8 hex digits (Unicode astral planes, new in C++11)

\0 = \00 = \000 = octal ecape for null character

If you do want an actual digit character after a \0, then yes, I recommend string concatenation. Note that the whitespace between the parts of the literal is optional, so you can write "\0""0".

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