std::isalnum<div class="t-tr-text">（std :: locale的）<div class="t-tr-dropdown"><div><div><div class="t-tr-dropdown-arrow-border"></div><div class="t-tr-dropdown-arrow"></div><div class="t-tr-dropdown-h">Original:</div><div class="t-tr-dropdown-orig">(std::locale)</div><div class="t-tr-dropdown-notes">The text has been machine-translated via [http://translate.google.com Google Translate].<br/> You can help to correct and verify the translation. Click [http://en.cppreference.com/w/Cppreference:MachineTranslations here] for instructions.</div></div></div></div></div>

 

C++

语言

概念

实用工具库

字符串库

集装箱库

算法库

迭代器库

Numerics库

输入/输出库

本地化库

正则表达式库 （C++11）

原子操作库 （C++11）

线程的支持库 （C++11）

 

本地化库

语言环境方面 Original: Locales and facets The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
locale
use_facet	has_facet
字符分类 Original: Character classification The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
isspace isblank （C++11） iscntrl isupper islower isalpha	isdigit ispunct isxdigit isalnum isprint isgraph
转换 Original: Conversions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
toupper tolower	wstring_convert （C++11） wbuffer_convert （C++11）
小面类的基类 Original: Facet category base classes The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
ctype_base codecvt_base messages_base	time_base money_base
小面类 Original: Facet categories The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
ctype ctype<char> codecvt collate messages time_get time_put	num_get num_put numpunct money_get money_put moneypunct
特定于语言环境的方面 Original: Locale-specific facets The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
ctype_byname ctype_byname<char> codecvt_byname messages_byname collate_byname	time_get_byname time_put_byname numpunct_byname moneypunct_byname
代码转换方面 Original: Code conversion facets The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
codecvt_utf8 （C++11） codecvt_utf16 （C++11）	codecvt_utf8_utf16 （C++11） codecvt_mode （C++11）
C语言环境 Original: C locale The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
setlocale localeconv lconv	LC_ALL LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC LC_TIME

 

Defined in header <locale>
template< class charT > bool isalnum( charT ch, const locale& loc );

给定语言环境的std::ctype方面的检查，如果给定的字符的字母数字字符.

Original:

Checks if the given character classified as an alphanumeric character by the given locale's std::ctype facet.

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参数

ch	-	字符 Original: character The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
loc	-	语言环境 Original: locale The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

返回值

返回true如果该字符是字母数字分类，false否则.

Original:

Returns true if the character is classified as alphanumeric, false otherwise.

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可能的实现

template< class charT > bool isalnum( charT ch, const std::locale& loc ) { return std::use_facet<std::ctype<charT>>(loc).is(std::ctype_base::alnum, ch); }

为例

演示isalnum（）使用不同的语言环境（OS特定）.

Original:

Demonstrates the use of isalnum() with different locales (OS-specific).

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#include <iostream>
#include <locale>
int main()
{
    const wchar_t c = L'\u2135'; // mathematical symbol aleph
 
    std::locale loc1("C");
    std::cout << "isalnum('ℵ', C locale) returned "
               << std::boolalpha << std::isalnum(c, loc1) << '\n';
 
    std::locale loc2("en_US.UTF-8");
    std::cout << "isalnum('ℵ', Unicode locale) returned "
              << std::boolalpha << std::isalnum(c, loc2) << '\n';
}

Output:

isalpha('ℵ​', C locale) returned false
isalpha('ℵ', Unicode locale) returned true

另请参阅

isalnum	检查如果一个字符是字母数字 Original: checks if a character is alphanumeric The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数）
iswalnum	检查是否使用了一个宽字符是字母数字 Original: checks if a wide character is alphanumeric The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数）