#include <iostream>
#include <regex>
 
int main()
{
    std::regex const pattern { R"(\w)" };
    std::cout << R"('\w' match with 'a': )" << std::boolalpha << 
        std::regex_match("a", pattern) << std::endl;
        
    std::cout << R"('\w' match with '1': )" << std::boolalpha << 
        std::regex_match("1", pattern) << std::endl;
        
    std::cout << R"('\w' match with '&': )" << std::boolalpha << 
        std::regex_match("&", pattern) << std::endl;
}