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std::basic_..._last_not_of(3) C++ Standard Libarystd::basic_..._last_not_of(3) NAME std::basic_string::find_last_not_of - std::ba- sic_string::find_last_not_of Synopsis size_type find_last_not_of( const basic_string& str, (noex- cept since C++11) size_type pos = npos ) (1) (const- expr since C++20) const; size_type find_last_not_of( const CharT* s, size_type pos, size_type (2) (const- expr since C++20) count ) const; size_type find_last_not_of( const CharT* s, size_type (3) (const- expr since C++20) pos = npos ) const; size_type find_last_not_of( CharT ch, size_type pos = (4) (noex- cept since C++11) npos ) const; (const- expr since C++20) template< class StringViewLike > size_type (since C++17) find_last_not_of( const StringViewLike& t, (5) (const- expr since C++20) size_type pos = npos ) const noexcept(/* see below */); Finds the last character equal to none of the characters in the given character sequence. The search considers only the range [0, pos]. If all char- acters in the range can be found in the given character sequence, npos will be re- turned. 1) Finds the last character equal to none of characters in str. 2) Finds the last character equal to none of characters in the range [s, s + count). This range can include null characters. If [s, s + count) is not a valid range, the behavior is undefined. 3) Finds the last character equal to none 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). If [s, s + Traits::length(s)) is not a valid range, the behavior is undefined. 4) Finds the last character not equal to ch. 5) Implicitly converts t to a string view sv as if by std::ba- sic_string_view<CharT, Traits> sv = t;, then finds the last character equal to none 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 to end search count - length of character string identifying characters to search for s - pointer to a character string identifying characters to search for ch - character identifying characters 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. 5) 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 ef- fect (strong exception safety guarantee). Example // Run this code #include <iostream> #include <string> void show_pos(const std::string& str, std::string::size_type found) { if (found != std::string::npos) std::cout << '[' << found << "] = \'" << str[found] << "\'\n"; else std::cout << "not found\n"; } int main() { std::string str{"abc_123"}; char const* skip_set{"0123456789"}; std::string::size_type str_last_pos{std::string::npos}; show_pos(str, str.find_last_not_of(skip_set)); // [3] = '_' str_last_pos = 2; show_pos(str, str.find_last_not_of(skip_set, str_last_pos)); // [2] = 'c' str_last_pos = 2; show_pos(str, str.find_last_not_of('c', str_last_pos)); // [1] = 'b' const char arr[]{'3', '4', '5'}; show_pos(str, str.find_last_not_of(arr)); // [5] = '2' str_last_pos = 2; std::string::size_type skip_set_size{4}; show_pos(str, str.find_last_not_of(skip_set, str_last_pos, skip_set_size)); // [2] = 'c' show_pos(str, str.find_last_not_of("abc")); // [6] = '3' str_last_pos = 2; show_pos(str, str.find_last_not_of("abc", str_last_pos)); // not found } Output: [3] = '_' [2] = 'c' [1] = 'b' [5] = '2' [2] = 'c' [6] = '3' not found Defect reports The following behavior-changing defect reports were applied retroac- tively to previously published C++ standards. DR Applied to Behavior as published Cor- rect behavior LWG 141 C++98 overload (1) could only return npos the search range is if pos >= size() [0, size()) in this case LWG 847 C++98 there was no exception safety added strong exception guarantee safety guarantee LWG 2064 C++11 overloads (3,4) were noexcept removed LWG 2946 C++17 overload (5) caused ambiguity in avoided by making it a some cases template C++11 noexcept for overloads (4,5) were P1148R0 C++17 accidentally dropped by restored LWG2064/LWG2946 See also 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_of find last occurrence of characters (public member function) find last absence of characters find_last_not_of (public member function of std::ba- sic_string_view<CharT,Traits>) Category: * conditionally noexcept http://cppreference.com 2024.06.10 std::basic_..._last_not_of(3)
NAME | Synopsis | Parameters | Return value | Exceptions | Example | Output: | See also | Category:
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