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

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 characters in the range can be found in the given character sequence, npos will be returned.

In all cases, equality is checked by calling Traits::eq .

Parameters

Return value

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

Exceptions

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

Example

#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
}

[3] = '_'
[2] = 'c'
[1] = 'b'
[5] = '2'
[2] = 'c'
[6] = '3'
not found

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also