`<locale>` 函数

项目
10/12/2023

has_facet
isalnum
isalpha
iscntrl
isdigit
isgraph
islower
isprint
ispunct
isspace
isupper
isxdigit
tolower
toupper
use_facet

has_facet

测试某一特定 facet 是否存储在指定区域设置中。

template <class Facet>
bool has_facet(const locale& Loc);

参数

Loc
测试其中是否存在 facet 的区域设置。

返回值

如果已测试区域设置中存在 facet，则为 true；如果不存在，则为 false。

备注

模板函数可用于检查在调用 use_facet 之前是否在区域设置中列出了非强制性 facet，以避免在不存在 facet 时将引发的异常。

示例

// locale_has_facet.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>
using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   bool result = has_facet <ctype<char> > ( loc );
   cout << result << endl;
}

isalnum

测试区域设置中的某一元素是否是字母字符或数字字符。

template <class CharType>
bool isalnum(CharType Ch, const locale& Loc)

参数

Ch
要测试的字母数字元素。

Loc
包含要测试的字母数字元素的区域设置。

返回值

如果测试的元素是字母数字元素，则为 true；如果不是，则为 false。

示例

// locale_isalnum.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>

using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   bool result1 = isalnum ( 'L', loc);
   bool result2 = isalnum ( '@', loc);
   bool result3 = isalnum ( '3', loc);

   if ( result1 )
      cout << "The character 'L' in the locale is "
           << "alphanumeric." << endl;
   else
      cout << "The character 'L' in the locale is "
           << " not alphanumeric." << endl;

   if ( result2 )
      cout << "The character '@' in the locale is "
           << "alphanumeric." << endl;
   else
      cout << "The character '@' in the locale is "
           << " not alphanumeric." << endl;

   if ( result3 )
      cout << "The character '3' in the locale is "
           << "alphanumeric." << endl;
   else
      cout << "The character '3' in the locale is "
           << " not alphanumeric." << endl;
}

The character 'L' in the locale is alphanumeric.
The character '@' in the locale is  not alphanumeric.
The character '3' in the locale is alphanumeric.

isalpha

测试区域设置中的某一元素是否是字母字符。

template <class CharType>
bool isalpha(CharType Ch, const locale& Loc)

参数

Ch
要进行测试的元素。

Loc
包含要测试的字母元素的区域设置。

返回值

如果测试的元素是字母元素，则为 true；如果不是，则为 false。

注解

模板函数返回 use_facet<ctype<CharType>>( Loc)。 is( ctype<CharType>:: alpha, Ch)。

示例

// locale_isalpha.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>

using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   bool result1 = isalpha ( 'L', loc);
   bool result2 = isalpha ( '@', loc);
   bool result3 = isalpha ( '3', loc);

   if ( result1 )
      cout << "The character 'L' in the locale is "
           << "alphabetic." << endl;
   else
      cout << "The character 'L' in the locale is "
           << " not alphabetic." << endl;

   if ( result2 )
      cout << "The character '@' in the locale is "
           << "alphabetic." << endl;
   else
      cout << "The character '@' in the locale is "
           << " not alphabetic." << endl;

   if ( result3 )
      cout << "The character '3' in the locale is "
           << "alphabetic." << endl;
   else
      cout << "The character '3' in the locale is "
           << " not alphabetic." << endl;
}

iscntrl

测试区域设置中的某一元素是否是控制字符。

template <class CharType>
bool iscntrl(CharType Ch, const locale& Loc)

参数

Ch
要进行测试的元素。

Loc
包含要测试的元素的区域设置。

返回值

如果测试的元素是控制字符，返回值为 true；如果不是，返回值为 false。

备注

模板函数返回 use_facet<ctype<CharType>>( Loc)。 is( ctype<CharType>:: cntrl, Ch)。

示例

// locale_iscntrl.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>

using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   bool result1 = iscntrl ( 'L', loc );
   bool result2 = iscntrl ( '\n', loc );
   bool result3 = iscntrl ( '\t', loc );

   if ( result1 )
      cout << "The character 'L' in the locale is "
           << "a control character." << endl;
   else
      cout << "The character 'L' in the locale is "
           << " not a control character." << endl;

   if ( result2 )
      cout << "The character-set 'backslash-n' in the locale\n is "
           << "a control character." << endl;
   else
      cout << "The character-set 'backslash-n' in the locale\n is "
           << " not a control character." << endl;

   if ( result3 )
      cout << "The character-set 'backslash-t' in the locale\n is "
           << "a control character." << endl;
   else
      cout << "The character-set 'backslash-n' in the locale \n is "
           << " not a control character." << endl;
}

isdigit

测试区域设置中的某一元素是否是数字字符。

template <class CharType>
bool isdigit(CharType Ch, const locale& Loc)

参数

Ch
要进行测试的元素。

Loc
包含要测试的元素的区域设置。

返回值

如果测试的元素是数字字符，则为 true；如果不是，则为 false。

注解

模板函数返回 use_facet<ctype<CharType>>( Loc)。 is( ctype<CharType>:: digit, Ch)。

示例

// locale_is_digit.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>

using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   bool result1 = isdigit ( 'L', loc );
   bool result2 = isdigit ( '@', loc );
   bool result3 = isdigit ( '3', loc );

   if ( result1 )
      cout << "The character 'L' in the locale is "
           << "a numeric character." << endl;
   else
      cout << "The character 'L' in the locale is "
           << " not a numeric character." << endl;

   if ( result2 )
      cout << "The character '@' in the locale is "
           << "a numeric character." << endl;
   else
      cout << "The character '@' in the locale is "
           << " not a numeric character." << endl;

   if ( result3 )
      cout << "The character '3' in the locale is "
           << "a numeric character." << endl;
   else
      cout << "The character '3' in the locale is "
           << " not a numeric character." << endl;
}

isgraph

测试区域设置中的某一元素是否是字母数字字符或标点字符。

template <class CharType>
bool isgraph(CharType Ch, const locale& Loc)

参数

Ch
要进行测试的元素。

Loc
包含要测试的元素的区域设置。

返回值

如果测试的元素是字母数字字符或标点字符，则为 true；如果不是，则为 false。

备注

模板函数返回 use_facet<ctype<CharType>>( Loc)。 is( ctype<CharType>:: graph, Ch)。

示例

// locale_is_graph.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>

using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   bool result1 = isgraph ( 'L', loc );
   bool result2 = isgraph ( '\t', loc );
   bool result3 = isgraph ( '.', loc );

   if ( result1 )
      cout << "The character 'L' in the locale is\n "
           << "an alphanumeric or punctuation character." << endl;
   else
      cout << "The character 'L' in the locale is\n "
           << " not an alphanumeric or punctuation character." << endl;

   if ( result2 )
      cout << "The character 'backslash-t' in the locale is\n "
           << "an alphanumeric or punctuation character." << endl;
   else
      cout << "The character 'backslash-t' in the locale is\n "
           << "not an alphanumeric or punctuation character." << endl;

   if ( result3 )
      cout << "The character '.' in the locale is\n "
           << "an alphanumeric or punctuation character." << endl;
   else
      cout << "The character '.' in the locale is\n "
           << " not an alphanumeric or punctuation character." << endl;
}

islower

测试区域设置中的某一元素是否是小写。

template <class CharType>
bool islower(CharType Ch, const locale& Loc)

参数

Ch
要进行测试的元素。

Loc
包含要测试的元素的区域设置。

返回值

如果测试的元素是小写字符，则为 true；如果不是，则为 false。

备注

模板函数返回 use_facet<ctype<CharType>>( Loc)。 is( ctype<CharType>:: lower, Ch)。

示例

// locale_islower.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>

using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   bool result1 = islower ( 'L', loc );
   bool result2 = islower ( 'n', loc );
   bool result3 = islower ( '3', loc );

   if ( result1 )
      cout << "The character 'L' in the locale is "
           << "a lowercase character." << endl;
   else
      cout << "The character 'L' in the locale is "
           << " not a lowercase character." << endl;

   if ( result2 )
      cout << "The character 'n' in the locale is "
           << "a lowercase character." << endl;
   else
      cout << "The character 'n' in the locale is "
           << " not a lowercase character." << endl;

   if ( result3 )
      cout << "The character '3' in the locale is "
           << "a lowercase character." << endl;
   else
      cout << "The character '3' in the locale is "
           << " not a lowercase character." << endl;
}

isprint

测试区域设置中的某一元素是否是可打印字符。

template <class CharType>
bool isprint(CharType Ch, const locale& Loc)

参数

Ch
要进行测试的元素。

Loc
包含要测试的元素的区域设置。

返回值

如果测试的元素是可打印元素，则为 true；如果不是，则为 false。

备注

模板函数返回 use_facet<ctype<CharType>>( Loc)。 is( ctype<CharType>:: print, Ch)。

示例

// locale_isprint.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>
using namespace std;

int main( )
{
   locale loc ( "German_Germany" );

   bool result1 = isprint ( 'L', loc );
   if ( result1 )
      cout << "The character 'L' in the locale is "
           << "a printable character." << endl;
   else
      cout << "The character 'L' in the locale is "
           << " not a printable character." << endl;

   bool result2 = isprint( '\t', loc );
   if ( result2 )
      cout << "The character 'backslash-t' in the locale is "
           << "a printable character." << endl;
   else
      cout << "The character 'backslash-t' in the locale is "
           << " not a printable character." << endl;

   bool result3 = isprint( '\n', loc );
   if ( result3 )
      cout << "The character 'backslash-n' in the locale is "
           << "a printable character." << endl;
   else
      cout << "The character 'backslash-n' in the locale is "
           << " not a printable character." << endl;
}

ispunct

测试区域设置中的某一元素是否是标点字符。

template <class CharType>
bool ispunct(CharType Ch, const locale& Loc)

参数

Ch
要进行测试的元素。

Loc
包含要测试的元素的区域设置。

返回值

如果测试的元素是标点字符，则为 true；如果不是，则为 false。

注解

模板函数返回 use_facet<ctype<CharType>>( Loc)。 is( ctype<CharType>:: punct, Ch)。

示例

// locale_ispunct.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>

using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   bool result1 = ispunct ( 'L', loc );
   bool result2 = ispunct ( ';', loc );
   bool result3 = ispunct ( '*', loc );

   if ( result1 )
      cout << "The character 'L' in the locale is "
           << "a punctuation character." << endl;
   else
      cout << "The character 'L' in the locale is "
           << " not a punctuation character." << endl;

   if ( result2 )
      cout << "The character ';' in the locale is "
           << "a punctuation character." << endl;
   else
      cout << "The character ';' in the locale is "
           << " not a punctuation character." << endl;

   if ( result3 )
      cout << "The character '*' in the locale is "
           << "a punctuation character." << endl;
   else
      cout << "The character '*' in the locale is "
           << " not a punctuation character." << endl;
}

isspace

测试区域设置中的某一元素是否是空白字符。

template <class CharType>
bool isspace(CharType Ch, const locale& Loc)

参数

Ch
要进行测试的元素。

Loc
包含要测试的元素的区域设置。

返回值

如果测试的元素是空白字符，则为 true；如果不是，则为 false。

备注

模板函数返回 use_facet<ctype<CharType>>( Loc)。 is( ctype<CharType>:: space, Ch)。

示例

// locale_isspace.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>

using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   bool result1 = isspace ( 'L', loc );
   bool result2 = isspace ( '\n', loc );
   bool result3 = isspace ( ' ', loc );

   if ( result1 )
      cout << "The character 'L' in the locale is "
           << "a whitespace character." << endl;
   else
      cout << "The character 'L' in the locale is "
           << " not a whitespace character." << endl;

   if ( result2 )
      cout << "The character 'backslash-n' in the locale is "
           << "a whitespace character." << endl;
   else
      cout << "The character 'backslash-n' in the locale is "
           << " not a whitespace character." << endl;

   if ( result3 )
      cout << "The character ' ' in the locale is "
           << "a whitespace character." << endl;
   else
      cout << "The character ' ' in the locale is "
           << " not a whitespace character." << endl;
}

isupper

测试区域设置中的某一元素是否是大写。

template <class CharType>
bool isupper(CharType Ch, const locale& Loc)

参数

Ch
要进行测试的元素。

Loc
包含要测试的元素的区域设置。

返回值

如果测试的元素是大写字符，则为 true；如果不是，则为 false。

备注

模板函数返回 use_facet<ctype<CharType>>( Loc)。 is( ctype<CharType>:: upper, Ch)。

示例

// locale_isupper.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>

using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   bool result1 = isupper ( 'L', loc );
   bool result2 = isupper ( 'n', loc );
   bool result3 = isupper ( '3', loc );

   if ( result1 )
      cout << "The character 'L' in the locale is "
           << "a uppercase character." << endl;
   else
      cout << "The character 'L' in the locale is "
           << " not a uppercase character." << endl;

   if ( result2 )
      cout << "The character 'n' in the locale is "
           << "a uppercase character." << endl;
   else
      cout << "The character 'n' in the locale is "
           << " not a uppercase character." << endl;

   if ( result3 )
      cout << "The character '3' in the locale is "
           << "a uppercase character." << endl;
   else
      cout << "The character '3' in the locale is "
           << " not a uppercase character." << endl;
}

isxdigit

测试区域设置中的某一元素是否是用于表示十六进制数字的字符。

template <class CharType>
bool isxdigit(CharType Ch, const locale& Loc)

参数

Ch
要进行测试的元素。

Loc
包含要测试的元素的区域设置。

返回值

如果测试的元素是用于表示十六进制数字的字符，则为 true；如果不是，则为 false。

注解

模板函数返回 use_facet<ctype<CharType>>( Loc)。 is( ctype<CharType>:: xdigit, Ch)。

十六进制数字以 16 为基数来表示数字，使用 0 到 9 的数字加上不区分大小写的 A 到 F 的字母来表示 0 到 15 的十进制数字。

示例

// locale_isxdigit.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>

using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   bool result1 = isxdigit ( '5', loc );
   bool result2 = isxdigit ( 'd', loc );
   bool result3 = isxdigit ( 'q', loc );

   if ( result1 )
      cout << "The character '5' in the locale is "
           << "a hexidecimal digit-character." << endl;
   else
      cout << "The character '5' in the locale is "
           << " not a hexidecimal digit-character." << endl;

   if ( result2 )
      cout << "The character 'd' in the locale is "
           << "a hexidecimal digit-character." << endl;
   else
      cout << "The character 'd' in the locale is "
           << " not a hexidecimal digit-character." << endl;

   if ( result3 )
      cout << "The character 'q' in the locale is "
           << "a hexidecimal digit-character." << endl;
   else
      cout << "The character 'q' in the locale is "
           << " not a hexidecimal digit-character." << endl;
}

tolower

将字符转换为小写。

template <class CharType>
CharType tolower(CharType Ch, const locale& Loc)

参数

Ch
要转换为小写的字符。

Loc
包含要转换的字符的区域设置。

返回值

被转换为小写的字符。

备注

模板函数返回 use_facet<ctype<CharType>>( Loc)。 tolower( Ch)。

示例

// locale_tolower.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>
using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   char result1 = tolower ( 'H', loc );
   cout << "The lower case of 'H' in the locale is: "
        << result1 << "." << endl;
   char result2 = tolower ( 'h', loc );
   cout << "The lower case of 'h' in the locale is: "
        << result2 << "." << endl;
   char result3 = tolower ( '$', loc );
   cout << "The lower case of '$' in the locale is: "
        << result3 << "." << endl;
}

toupper

将字符转换为大写。

template <class CharType>
CharType toupper(CharType Ch, const locale& Loc)

参数

Ch
要转换为大写的字符。

Loc
包含要转换的字符的区域设置。

返回值

转换为大写的字符。

备注

模板函数返回 use_facet<ctype<CharType>>( Loc)。 toupper( Ch)。

示例

// locale_toupper.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>
using namespace std;

int main( )
{
   locale loc ( "German_Germany" );
   char result1 = toupper ( 'h', loc );
   cout << "The upper case of 'h' in the locale is: "
        << result1 << "." << endl;
   char result2 = toupper ( 'H', loc );
   cout << "The upper case of 'H' in the locale is: "
        << result2 << "." << endl;
   char result3 = toupper ( '$', loc );
   cout << "The upper case of '$' in the locale is: "
        << result3 << "." << endl;
}

use_facet

返回对区域设置中存储的某一指定类型 facet 的引用。

template <class Facet>
const Facet& use_facet(const locale& Loc);

参数

Loc
包含所引用的 facet 类型的 const 区域设置。

返回值

对 Facet 类的 facet 的引用包含在自变量区域设置中。

备注

只要存在包含区域设置的任何副本，则模板函数返回的对 facet 的引用保持有效。如果自变量区域设置中没有列出 Facet 类的此类 facet 对象，则该函数将引发 bad_cast 异常。

示例

// locale_use_facet.cpp
// compile with: /EHsc
#include <locale>
#include <iostream>
using namespace std;

int main( )
{
   locale loc1 ( "German_Germany" ), loc2 ( "English_Australia" );
   bool result1 = use_facet<ctype<char> > ( loc1 ).is(
   ctype_base::alpha, 'a'
);
   bool result2 = use_facet<ctype<char> > ( loc2 ).is( ctype_base::alpha, '!'
   );

   if ( result1 )
      cout << "The character 'a' in locale loc1 is alphabetic."
           << endl;
   else
      cout << "The character 'a' in locale loc1 is not alphabetic."
           << endl;

   if ( result2 )
      cout << "The character '!' in locale loc2 is alphabetic."
           << endl;
   else
      cout << "The character '!' in locale loc2 is not alphabetic."
           << endl;
}

The character 'a' in locale loc1 is alphabetic.
The character '!' in locale loc2 is not alphabetic.

另请参阅

<区域设置>

通过

<locale> 函数

has_facet

参数

返回值

备注

示例

isalnum

参数

返回值

示例

isalpha

参数

返回值

注解

示例

iscntrl

参数

返回值

备注

示例

isdigit

参数

返回值

注解

示例

isgraph

参数

返回值

备注

示例

islower

参数

返回值

备注

示例

isprint

参数

返回值

备注

示例

ispunct

参数

返回值

注解

示例

isspace

参数

返回值

备注

示例

isupper

参数

返回值

备注

示例

isxdigit

参数

返回值

注解

示例

tolower

参数

返回值

备注

示例

toupper

参数

返回值

备注

示例

use_facet

参数

返回值

备注

示例

另请参阅

反馈

其他资源

`<locale>` 函数