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Difference between revisions of "cpp/locale/islower"

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< cpp‎ | locale
m (r2.7.3) (Robot: Adding de, es, fr, it, ja, pt, ru, zh)
m (→‎Example: Use Unicode/C++23 name for 'π' (i.e. capitalized), + `islower` VS `isupper`.)
 
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{{cpp/title | islower{{small|(std::locale)}}}}
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{{cpp/title|islower{{small|(std::locale)}}}}
 
{{cpp/locale/navbar}}
 
{{cpp/locale/navbar}}
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{{ddcl|header=locale|
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{{ddcl | header=locale |
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template< class CharT >
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template< class charT >
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bool islower( CharT ch, const locale& loc );
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bool islower( charT ch, const locale& loc );
+
 
}}
 
}}
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Checks if the given character is classified as a lowercase alphabetic character by the given locale's {{lc|std::ctype}} facet.
−
 
+
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Checks if the given character classified as a lowercase alphabetic character by the given locale's {{c|std::ctype}} facet.
+
  
 
===Parameters===
 
===Parameters===
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{{param list begin}}
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{{par begin}}
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{{param list item | ch | character}}
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{{par|ch|character}}
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{{param list item | loc | locale }}
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{{par|loc|locale}}
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{{param list end}}
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{{par end}}
  
 
===Return value===
 
===Return value===
−
 
 
Returns {{c|true}} if the character is classified as lowercase, {{c|false}} otherwise.
 
Returns {{c|true}} if the character is classified as lowercase, {{c|false}} otherwise.
  
 
===Possible implementation===
 
===Possible implementation===
 
{{eq fun
 
{{eq fun
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| 1=
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|1=
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template< class charT >
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template<class CharT>
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bool islower( charT ch, const std::locale& loc ) {
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bool islower(CharT ch, const std::locale& loc)
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     return std::use_facet<std::ctype<charT>>(loc).is(std::ctype_base::lower, ch);
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{
 +
     return std::use_facet<std::ctype<CharT>>(loc).is(std::ctype_base::lower, ch);
 
}
 
}
 
}}
 
}}
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===Example===
 
===Example===
 
{{example
 
{{example
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| Demonstrates the use of islower() with different locales (OS-specific).
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|Demonstrates the use of {{tt|islower()}} with different locales (OS-specific).
−
| code=
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|code=
 
#include <iostream>
 
#include <iostream>
 
#include <locale>
 
#include <locale>
 +
 
int main()
 
int main()
 
{
 
{
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     const wchar_t c = L'\u03c0'; // greek small letter pi
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     const wchar_t c = L'\u03c0'; // GREEK SMALL LETTER PI
−
+
 
 
     std::locale loc1("C");
 
     std::locale loc1("C");
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     std::cout << "islower('π​', C locale) returned "
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     std::cout << std::boolalpha
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              << std::boolalpha << std::islower(c, loc1) << '\n';
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              << "islower('π', C locale) returned "
−
+
              << std::islower(c, loc1) << '\n'
 +
              << "isupper('π', C locale) returned "
 +
              << std::isupper(c, loc1) << '\n';
 +
 
 
     std::locale loc2("en_US.UTF8");
 
     std::locale loc2("en_US.UTF8");
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     std::cout << "islower('π​', Unicode locale) returned "
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     std::cout << "islower('π', Unicode locale) returned "
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               << std::boolalpha << std::islower(c, loc2) << '\n';
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               << std::islower(c, loc2) << '\n'
 +
              << "isupper('π', Unicode locale) returned "
 +
              << std::isupper(c, loc2) << '\n';
 
}
 
}
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| output=
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|p=true
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islower('π​', C locale) returned false
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|output=
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islower('π​', Unicode locale) returned true
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islower('π', C locale) returned false
 +
isupper('π', C locale) returned false
 +
islower('π', Unicode locale) returned true
 +
isupper('π', Unicode locale) returned false
 
}}
 
}}
  
 
===See also===
 
===See also===
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{{dcl list begin}}
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{{dsc begin}}
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{{dcl list template | cpp/string/byte/dcl list islower}}
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{{dsc inc|cpp/string/byte/dsc islower}}
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{{dcl list template | cpp/string/wide/dcl list iswlower}}
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{{dsc inc|cpp/string/wide/dsc iswlower}}
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{{dcl list end}}
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{{dsc end}}
  
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[[de:cpp/locale/islower]]
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{{langlinks|de|es|fr|it|ja|pt|ru|zh}}
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[[es:cpp/locale/islower]]
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−
[[fr:cpp/locale/islower]]
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−
[[it:cpp/locale/islower]]
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−
[[ja:cpp/locale/islower]]
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−
[[pt:cpp/locale/islower]]
+
−
[[ru:cpp/locale/islower]]
+
−
[[zh:cpp/locale/islower]]
+

Latest revision as of 05:59, 4 October 2023

 
C++
 
Localization library
 
Defined in header <locale>
template< class CharT >
bool islower( CharT ch, const locale& loc );

Checks if the given character is classified as a lowercase alphabetic character by the given locale's std::ctype facet.

Contents

[edit] Parameters

ch - character
loc - locale

[edit] Return value

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

[edit] Possible implementation

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

[edit] Example

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

Run this code
#include <iostream>
#include <locale>
 
int main()
{
    const wchar_t c = L'\u03c0'; // GREEK SMALL LETTER PI
 
    std::locale loc1("C");
    std::cout << std::boolalpha
              << "islower('π', C locale) returned "
              << std::islower(c, loc1) << '\n'
              << "isupper('π', C locale) returned "
              << std::isupper(c, loc1) << '\n';
 
    std::locale loc2("en_US.UTF8");
    std::cout << "islower('π', Unicode locale) returned "
              << std::islower(c, loc2) << '\n'
              << "isupper('π', Unicode locale) returned "
              << std::isupper(c, loc2) << '\n';
}

Possible output: 

islower('π', C locale) returned false
isupper('π', C locale) returned false
islower('π', Unicode locale) returned true
isupper('π', Unicode locale) returned false

[edit] See also

 checks if a character is lowercase
(function) [edit]
checks if a wide character is lowercase
(function) [edit]
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