Regex single UTF-8 Character in std::string

RegexUTF-8.c

#include <iostream>
#include <regex>

int main() {
    std::string input = "你好，world!";
    std::smatch matches;
    auto regex = std::regex("([\\x00-\\x7F]|([\\xC0-\\xF7][\\x80-\\xBF]*))");
    std::sregex_iterator begin(input.begin(),input.end(),regex);
    std::sregex_iterator end;
    for (auto i = begin;i!=end;++i) {
        std::cout<<"Match: "<<i->str()<<std::endl;
    }
    return 0;
}