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

For C I would use toupper after adjusting the C locale in the current thread.

setlocale(LC_CTYPE, "en_US.UTF8");

For C++ I would use the toupper method of std::ctype:

std::locale loc;

auto& f = std::use_facet>(loc);

char str[80] = "Hello World";

f.toupper(str, str+strlen(str));