[ Web Proxy ]
URL:
Viewing: http://ru.cppreference.com/cpp/string/basic_string/rfind [Back]  [Original]
std::basic_string<CharT,Traits,Allocator>::rfind cppreference.com
cppreference.com

std::basic_string<CharT,Traits,Allocator>::rfind

cppreference.com
 
C++
(C++20)
(C++20)
(C++11)
(C++20)
/
(C++11)
(C++11)
(C++11)
(C++17)
 
 
std::basic_string
-
(C++23)
(DR*)
(DR*)
(C++17)
(DR*)
(DR*)
(DR*)
(DR*)
(DR*)
(C++23)
(DR*)
(C++23)
(C++23)
(C++23)  
(C++20)  
(C++20)
(C++23)
(C++17)
,
(C++14)
(C++20)(C++20)
/
( C++20)( C++20)( C++20)( C++20)( C++20)(C++20)
(C++11)(C++11)(C++11)
(C++11)(C++11)
(C++11)(C++11)(C++11)
(C++11)
(C++11)
(C++11)  (C++11)(C++11)(C++11)(C++20)
(C++17)(C++17)(C++17)(C++17)(C++20)
 
<tbody> </tbody> <tbody class="t-dcl-rev t-dcl-rev-num "> </tbody><tbody> </tbody> <tbody class="t-dcl-rev t-dcl-rev-num "> </tbody><tbody> </tbody> <tbody class="t-dcl-rev t-dcl-rev-num "> </tbody><tbody> </tbody> <tbody class="t-dcl-rev t-dcl-rev-num "> </tbody><tbody> </tbody> <tbody class="t-dcl-rev t-dcl-rev-num "> </tbody><tbody> </tbody>
(1)
size_type rfind( const basic_string& str, size_type pos = npos ) const;
 ( C++11)
size_type rfind( const basic_string& str, size_type pos = npos ) const noexcept;
 ( C++11)
( C++20)
constexpr size_type rfind( const basic_string& str, size_type pos = npos ) const noexcept;
 ( C++20)
(2)
size_type rfind( const CharT* s, size_type pos, size_type count ) const;
 ( C++20)
constexpr size_type rfind( const CharT* s, size_type pos, size_type count ) const;
 ( C++20)
(3)
size_type rfind( const CharT* s, size_type pos = npos ) const;
 ( C++20)
constexpr size_type rfind( const CharT* s, size_type pos = npos ) const;
 ( C++20)
(4)
size_type rfind( CharT ch, size_type pos = npos ) const;
 ( C++11)
size_type rfind( CharT ch, size_type pos = npos ) const noexcept;
 ( C++11)
( C++20)
constexpr size_type rfind( CharT ch, size_type pos = npos ) const noexcept;
 ( C++20)
(5)
template< class StringViewLike > size_type rfind( const StringViewLike& t, size_type pos = npos ) const noexcept(/* */);
 ( C++17)
( C++20)
template< class StringViewLike > constexpr size_type rfind( const StringViewLike& t, size_type pos = npos ) const noexcept(/* */);
 ( C++20)

, . pos ( , , , , pos). npos size()- 1 pos, .

1) , str.
2) , [s, s + count). .
[s, s + count) , .
3) , , s. Traits::length(s).
[s, s + Traits::length(s)) , .
4) , ch.
5) t sv, std::basic_string_view<CharT, Traits> sv = t;, , sv.
, std::is_convertible_v<const StringViewLike&,
std::basic_string_view<CharT, Traits>> true std::is_convertible_v<const StringViewLike&, const CharT*> false.

Traits::eq.

str
pos ,
count
s
ch
t ( std::basic_string_view)

npos, . , , .

(.. str.size(), count Traits::length(s) ), , rfind :

  • pos, pos < size();
  • size() , , pos == npos.

, size() , npos.

1,4) .
5)
noexcept:  
noexcept(std::is_nothrow_convertible_v<const T&, std::basic_string_view<CharT, Traits>>)

- , ( ). 

#include <iomanip>
#include <iostream>
#include <string>
 
void print(std::string::size_type n,
           std::string::size_type len,
           std::string const &s)
{
    if (n == std::string::npos)
        std::cout << " \n";
    else
        std::cout << ": " << std::quoted(s.substr(n, len)) << "  " << n << '\n';
}
 
int main()
{
    std::string::size_type n;
    std::string const s = "This is a string";
    
    //     
    n = s.rfind("is");
    print(n, 2, s);
    
    //  ,    4
    n = s.rfind("is", 4);
    print(n, 2, s);
    
    //   
    n = s.rfind('s');
    print(n, 1, s);
    
    //   
    n = s.rfind('q');
    print(n, 1, s);
    
    //   (  s.starts_with("This"))
    n = s.rfind("This", 0);
    print(n, 4, s);
}

: 

: "is"  5
: "is"  2
: "s"  10
 
: "This"  0

C++:

LWG 847 C++98
LWG 2064 C++11 (3,4) noexcept
LWG 2946 C++17 (5)
,
WG C++11
C++17 		noexcept (4,5)
LWG2064/LWG2946


(public -) []

(public -) []

(public -) []

(public -) []

(public -) []
(C++17)
(public - std::basic_string_view<CharT,Traits>) []
Web Proxy Viewer  |  New URL  |  Original Page