9.4.1 Unicode escape sequences

最新推荐文章于 2024-12-05 14:27:37 发布

原创最新推荐文章于 2024-12-05 14:27:37 发布 · 2k 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#character #literals #class #string #structure #encoding

c#/c++ 专栏收录该内容

333 篇文章

订阅专栏

博客主要介绍了C#中Unicode转义序列，它代表一个Unicode字符，会在标识符、字符串和字符字面量中处理。给出了转义序列的格式，指出C#用16位编码，超出范围的代码点无效。还通过示例展示了其使用及等价转换。

9.4.1 Unicode escape sequences
A Unicode escape sequence represents a Unicode character. Unicode escape
sequences are processed in
identifiers (§9.4.2), regular string literals (§9.4.4.5), and character
literals (§9.4.4.4). A Unicode character escape
is not processed in any other location (for example, to form an operator,
punctuator, or keyword).
unicode-escape-sequence::
/u hex-digit hex-digit hex-digit hex-digit
/U hex-digit hex-digit hex-digit hex-digit hex-digit hex-digit hex-digit
hex-digit
A Unicode escape sequence represents the single Unicode character formed by
the hexadecimal number
following the ./u. or ./U. characters. Since C# uses a 16-bit encoding of
Unicode characters in characters and
string values, a Unicode code point in the range U+10000 to U+10FFFF is
represented using two Unicode
surrogate code units. Unicode code points above 0x10FFFF are invalid and
are not supported.
Multiple translations are not performed. For instance, the string literal
./u005Cu005C. is equivalent to
./u005C. rather than ./.. [Note: The Unicode value /u005C is the character
./.. end note]
[Example: The example
Chapter 9 Lexical structure
55
class Class1
{
static void Test(bool /u0066) {
char c = ’/u0066’;
if (/u0066)
System.Console.WriteLine(c.ToString());
}
}
shows several uses of /u0066, which is the escape sequence for the letter
.f.. The program is equivalent to
class Class1
{
static void Test(bool f) {
char c = ’f’;
if (f)
System.Console.WriteLine(c.ToString());
}
}
end example]