std::basic_string<CharT,Traits,Allocator>::find_last_of
(1) | ||
size_type find_last_of( const basic_string& str, size_type pos = npos ) const; |
(until C++11) | |
size_type find_last_of( const basic_string& str, size_type pos = npos ) const noexcept; |
(since C++11) (until C++20) |
|
constexpr size_type find_last_of( const basic_string& str, size_type pos = npos ) const noexcept; |
(since C++20) | |
(2) | ||
size_type find_last_of( const CharT* s, size_type pos, size_type count ) const; |
(until C++11) | |
constexpr size_type find_last_of( const CharT* s, size_type pos, size_type count ) const; |
(since C++11) | |
(3) | ||
size_type find_last_of( const CharT* s, size_type pos = npos ) const; |
(until C++20) | |
constexpr size_type find_last_of( const CharT* s, size_type pos = npos ) const; |
(since C++20) | |
(4) | ||
size_type find_last_of( CharT ch, size_type pos = npos ) const; |
(until C++11) | |
size_type find_last_of( CharT ch, size_type pos = npos ) const noexcept; |
(since C++11) (until C++20) |
|
constexpr size_type find_last_of( CharT ch, size_type pos = npos ) const noexcept; |
(since C++20) | |
(5) | ||
template< class StringViewLike > size_type |
(since C++17) (until C++20) |
|
template< class StringViewLike > constexpr size_type |
(since C++20) | |
Finds the last character equal to one of characters in the given character sequence. The exact search algorithm is not specified. The search considers only the range [
0,
pos]
. If none of the characters in the given character sequence is present in the range, npos will be returned.
[
s,
s + count)
. This range can include null characters.std::basic_string_view<CharT, Traits>> is true and std::is_convertible_v<const StringViewLike&, const CharT*> is false.
In all cases, equality is checked by calling Traits::eq.
Contents |
[edit] Parameters
str | - | string identifying characters to search for |
pos | - | position at which the search is to finish |
count | - | length of character string identifying characters to search for |
s | - | pointer to a character string identifying characters to search for |
ch | - | character to search for |
t | - | object (convertible to std::basic_string_view) identifying characters to search for |
[edit] Return value
Position of the found character or npos if no such character is found.
[edit] Exceptions
If an exception is thrown for any reason, this function has no effect (strong exception safety guarantee).
[edit] Example
#include <iostream> #include <string> int main() { const std::string path = "/root/config"; auto const pos = path.find_last_of('/'); const auto leaf = path.substr(pos + 1); std::cout << leaf << '\n'; }
Output:
config
[edit] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR | Applied to | Behavior as published | Correct behavior |
---|---|---|---|
LWG 141 | C++98 | overload (1) could only return npos if pos >= size() | the search range is[ 0, size()) in this case
|
LWG 847 | C++98 | there was no exception safety guarantee | added strong exception safety guarantee |
LWG 2064 | C++11 | overloads (3,4) were noexcept | removed |
LWG 2946 | C++17 | overload (5) caused ambiguity in some cases | avoided by making it a template |
P1148R0 | C++11 C++17 |
noexcept for overloads (4,5) were accidently dropped by LWG2064/LWG2946 |
restored |
[edit] See also
finds the first occurrence of the given substring (public member function) | |
find the last occurrence of a substring (public member function) | |
find first occurrence of characters (public member function) | |
find first absence of characters (public member function) | |
find last absence of characters (public member function) | |
(C++17) |
find last occurrence of characters (public member function of std::basic_string_view<CharT,Traits> )
|