/in/foo.cc: In function 'std::string Jian(std::string, std::string)':
/in/foo.cc:33:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |  for(int i=0;i<temp.size();++i)
      |              ~^~~~~~~~~~~~
/in/foo.cc:36:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |   int num2=(i<str2.size()) ? (str2[i]-'0') : 0;
      |             ~^~~~~~~~~~~~