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

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size_type find_last_of ( const basic_string & str, size_type pos = npos ) const ;	(1)	(noexcept since C++11) (constexpr since C++20)
size_type find_last_of ( const CharT * s, size_type pos, size_type count ) const ;	(2)	(constexpr since C++20)
size_type find_last_of ( const CharT * s, size_type pos = npos ) const ;	(3)	(constexpr since C++20)
size_type find_last_of ( CharT ch, size_type pos = npos ) const ;	(4)	(noexcept since C++11) (constexpr since C++20)
template < class StringViewLike > size_type find_last_of ( const StringViewLike & t, size_type pos = npos ) const noexcept ( /* see below */ ) ;	(5)	(since C++17) (constexpr 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.

1) Finds the last character equal to one of characters in str .

2) Finds the last character equal to one of characters in range

s + count

. This range can include null characters.

s + count

is not a valid range , the behavior is undefined.

3) Finds the last character equal to one of characters in character string pointed to by s . The length of the string is determined by the first null character using Traits :: length ( s ) .

s + Traits :: length ( s )

is not a valid range , the behavior is undefined.

4) Finds the last character equal to ch .

5) Implicitly converts t to a string view sv as if by std:: basic_string_view < CharT, Traits > sv = t ; , then finds the last character equal to one of characters in sv .

This overload participates in overload resolution only if std:: is_convertible_v < const StringViewLike & ,
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 .

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

Return value

Position of the found character or npos if no such character is found.

Exceptions

1,4) Throws nothing.

noexcept specification:

noexcept ( std:: is_nothrow_convertible_v < const T & , std:: basic_string_view < CharT, Traits >> )

If an exception is thrown for any reason, this function has no effect ( strong exception safety guarantee ).

Example

Run this code

#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

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 accidentally dropped by LWG2064/LWG2946	restored

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find	finds the first occurrence of the given substring (public member function)
rfind	find the last occurrence of a substring (public member function)
find_first_of	find first occurrence of characters (public member function)
find_first_not_of	find first absence of characters (public member function)
find_last_not_of	find last absence of characters (public member function)
find_last_of	find last occurrence of characters (public member function of `std::basic_string_view<CharT,Traits>` )