#include <iostream>
#include <string>
#include <regex>
 
int main()
{
    std::regex pattern { "[a-e]" };
    std::cout << "'[a-e]' match with '': " << std::boolalpha << 
        std::regex_match("", pattern) << std::endl;
        
    std::cout << "'[a-e]' match with 'a': " << std::boolalpha << 
        std::regex_match("a", pattern) << std::endl;
        
    std::cout << "'[a-e]' match with 'e': " << std::boolalpha << 
        std::regex_match("e", pattern) << std::endl;
        
    std::cout << "'[a-e]' match with 'z': " << std::boolalpha << 
        std::regex_match("z", pattern) << std::endl;
        
    std::cout << "'[a-e]' match with 'ab': " << std::boolalpha << 
        std::regex_match("ab", pattern) << std::endl;
        
    pattern = "ab[c-f]";
    std::cout << "'ab[c-f]' match with '': " << std::boolalpha << 
        std::regex_match("", pattern) << std::endl;
        
    std::cout << "'ab[c-f]' match with 'abc': " << std::boolalpha << 
        std::regex_match("abc", pattern) << std::endl;
        
    std::cout << "'ab[c-f]' match with 'abz': " << std::boolalpha << 
        std::regex_match("abz", pattern) << std::endl;
}