/in/foo.cc: In member function 'std::string calculator::add_sub(std::string, std::string, bool)':
/in/foo.cc:25:30: warning: comparison of integer expressions of different signedness: 'int' and 'const long unsigned int' [-Wsign-compare]
   25 |                 for(int i=0;i<max(num1.size(),num2.size());i++)
      |                             ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:27:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |                         if(i>=num1.size())
      |                            ~^~~~~~~~~~~~~
/in/foo.cc:31:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |                         if(i>=num2.size())
      |                            ~^~~~~~~~~~~~~
/in/foo.cc:50:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |                         for(int i=0;i<num1.size();i++)
      |                                     ~^~~~~~~~~~~~