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Difference between revisions of "cpp/string/basic string/operator""s"

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< cpp‎ | string‎ | basic string
m (rv)
m (Minor fix.)
 
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{{cpp/title|n=literals::string_literals::|operator""s }}
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{{cpp/title|n=literals::string_literals::|operator""s}}
 
{{cpp/string/basic_string/navbar}}
 
{{cpp/string/basic_string/navbar}}
 
{{dcl begin}}
 
{{dcl begin}}
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{{dcl header | string}}
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{{dcl header|string}}
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{{dcl rev multi | num=1
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{{|num=1|=c++14|=c++20|
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| since1=c++14 | dcl1=
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std::string operator""s( const char* str, std::size_t len );
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std::string operator""s(const char *str, std::size_t len);
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| since2=c++20 | dcl2=
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constexpr std::string operator""s(const char *str, std::size_t len);
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}}
 
}}
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{{dcl | num=2 | since=c++20 | 1=
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{{dcl|num=2|since=c++20|
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constexpr std::u8string operator""s(const char8_t *str, std::size_t len);
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constexpr std::u8string operator""s( const char8_t* str,
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std::size_t len );
 
}}
 
}}
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{{dcl rev multi | num=3
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{{|num=3|=c++14|=c++20|
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| since1=c++14 | dcl1=
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std::u16string operator""s( const char16_t* str, std::size_t len );
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std::u16string operator""s(const char16_t *str, std::size_t len);
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| since2=c++20 | dcl2=
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constexpr std::u16string operator""s(const char16_t *str, std::size_t len);
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}}
 
}}
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{{|num=4|=c++14|=c++20|
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std::u32string operator""s( const char32_t* str, std::size_t len );
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std::u32string operator""s(const char32_t *str, std::size_t len);
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constexpr std::u32string operator""s(const char32_t *str, std::size_t len);
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}}
 
}}
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{{|num=5|=c++14|=c++20|
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| since1=c++14 | dcl1=
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std::wstring operator""s( const wchar_t* str, std::size_t len );
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std::wstring operator""s(const wchar_t *str, std::size_t len);
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| since2=c++20 | dcl2=
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constexpr std::wstring operator""s(const wchar_t *str, std::size_t len);
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Forms a string literal of the desired type.
 
Forms a string literal of the desired type.
  
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@1@ returns {{c|std::string{str, len} }}
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@1@ {{c|std::string{str, len} }}
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@2@ returns {{c|std::u8string{str, len} }}
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@2@ {{c|std::u8string{str, len} }}
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@3@ returns {{c|std::u16string{str, len} }}
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@3@ {{c|std::u16string{str, len} }}
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@4@ returns {{c|std::u32string{str, len} }}
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@4@ {{c|std::u32string{str, len} }}
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@5@ returns {{c|std::wstring{str, len} }}
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@5@ {{c|std::wstring{str, len} }}
  
 
===Parameters===
 
===Parameters===
 
{{par begin}}
 
{{par begin}}
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{{par | str | pointer to the beginning of the raw character array literal}}
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{{par|str|pointer to the beginning of the raw character array literal}}
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{{par | len | length of the raw character array literal}}
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{{par|len|length of the raw character array literal}}
 
{{par end}}
 
{{par end}}
  
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===Notes===
 
===Notes===
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These operators are declared in the namespace {{tt|std::literals::string_literals}}, where both {{tt|literals}} and {{tt|string_literals}} are inline namespaces. Access to these operators can be gained with {{c|using namespace std::literals}}, {{c|using namespace std::string_literals}}, and {{c|using namespace std::literals::string_literals}}.
+
These operators are declared in the namespace {{|std::literals::string_literals}}, where both {{tt|literals}} and {{tt|string_literals}} are inline namespaces. Access to these operators can be gained with
 +
{{c|using namespace std::literals}}
 +
{{c|using namespace std::string_literals}}
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{{c|using namespace std::literals::string_literals}}
  
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{{lc|std::chrono::duration}} also defines {{tt|operator""s}}, to represent literal seconds, but it is an arithmetic literal: {{c|10.0s}} and {{c|10s}} are ten seconds, but {{c|"10"s}} is a string.
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{{lc|std::chrono::duration}} also defines {{|operator""s}} to represent literal seconds, but it is an arithmetic literal: {{c|10.0s}} and {{c|10s}} are ten seconds, but {{c|"10"s}} is a string.
 +
 
 +
  
 
===Example===
 
===Example===
 
{{example
 
{{example
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| code=
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|code=
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#include <string>
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#include <iostream>
 
#include <iostream>
 +
 +
 +
 +
 +
 +
 +
 +
 +
  
 
int main()
 
int main()
 
{
 
{
 
     using namespace std::string_literals;
 
     using namespace std::string_literals;
−
 
+
 
     std::string s1 = "abc\0\0def";
 
     std::string s1 = "abc\0\0def";
 
     std::string s2 = "abc\0\0def"s;
 
     std::string s2 = "abc\0\0def"s;
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     std::cout << "s1: " << s1.size() << " \"" << s1 << "\"\n";
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     "s1: "s1
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     std::cout << "s2: " << s2.size() << " \"" << s2 << "\"\n";
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("";
 +
 +
     std::cout << "".() << \n;
 
}
 
}
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| p=true
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|output=
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| output=  
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s1: abc
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s1: 3 "abc"
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s2: 8
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s2: 8 "abc^@^@def"
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}}
 
}}
  
 
===See also===
 
===See also===
 
{{dsc begin}}
 
{{dsc begin}}
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{{dsc inc | cpp/string/basic_string/dsc constructor}}
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{{dsc inc|cpp/string/basic_string/dsc constructor
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}}
 
{{dsc end}}
 
{{dsc end}}
  
 
{{langlinks|de|es|fr|it|ja|pt|ru|zh}}
 
{{langlinks|de|es|fr|it|ja|pt|ru|zh}}

Latest revision as of 18:47, 16 December 2024

 
C++
 
Strings library
 
std::basic_string