/in/foo.cc: In function 'std::string Jia(const string&, const string&)':
/in/foo.cc:22:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |  for(int i=0;i<s.size();++i)
      |              ~^~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:53:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |    for(int i=0;i<(Outstr.size()-s.size());++i)
      |                ~^~~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:60:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |    for(int i=0;i<(s.size()-Outstr.size());++i)
      |                ~^~~~~~~~~~~~~~~~~~~~~~~~~