Convert a unicode String In C++ To Upper Case

Question

How we can convert a multi language string or unicode string to upper/lower case in C or C++.

Answer 1

If your system is already in UTF-8, by using std::use_facet, you can write:

#include <iostream>
#include <locale.h>

int main() {
    std::locale::global(std::locale(""));  // (*)
    std::wcout.imbue(std::locale());
    auto& f = std::use_facet<std::ctype<wchar_t>>(std::locale());

    std::wstring str = L"Zoë Saldaña played in La maldición del padre Cardona.";

    f.toupper(&str[0], &str[0] + str.size());
    std::wcout << str << std::endl;

    return 0;
}

And you get (http://ideone.com/AFHoHC):

ZOË SALDAÑA PLAYED IN LA MALDICIÓN DEL PADRE CARDONA.

If it don't work you will have to change (*) into std::locale::global(std::locale("en_US.UTF8")); or an UTF-8 locale you actually have on the plateform.