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 you want a sane and mature solution, look at IBM's ICU. Here's an example:

#include 
#include 
#include 

int main(){
    icu::UnicodeString us("óóßChloë");
    us.toUpper(); //convert to uppercase in-place
    std::string s;
    us.toUTF8String(s);
    std::cout<<"Upper: "<

Output:

Upper: ÓÓSSCHLOË
Lower: óósschloë

Note: In the later step SS isn't being treated as capital of German ß