#include <string>
#include <boost/algorithm/string/join.hpp>

int main() 
{ 
    std::basic_string<char16_t> string1 = u"aa"; 
    string1 += u",bb"; 
    printf("%d\n", string1.size()); 
     
    std::vector<std::basic_string<char16_t>> list; 
    list.push_back(u"aa"); 
    list.push_back(u"bb"); 
    std::basic_string<char16_t> string2 = boost::algorithm::join(list, u","); 
    printf("%d\n", string2.size()); 
}