string - C++ How to check if letter isalpha (not latin alphabet)

Question

so I need to see if my character is a letter. I tried using isalpha() function, however, if I try to pass not latin letter (for example ?, ?, ?, ?, ?, ?, ?, ū, ?) I get an error, that seems to state that isalpha function accepts only chars that in ASCII code are between 0 and 255. Is there any way to overcome this problem?

Answer 1

You can use a locale version of std::isalpha. Taking an example from the linked reference:

#include <iostream>
#include <locale>
int main()
{
    const wchar_t c = L'u042f'; // cyrillic capital letter ya

    std::locale loc1("C");
    std::cout << "isalpha('Я?', C locale) returned "
               << std::boolalpha << std::isalpha(c, loc1) << '
';

    std::locale loc2("en_US.UTF8");
    std::cout << "isalpha('Я', Unicode locale) returned "
              << std::boolalpha << std::isalpha(c, loc2) << '
';
}

Output:

isalpha('Я?', C locale) returned false
isalpha('Я', Unicode locale) returned true