/in/foo.cc: In function 'int main()':
/in/foo.cc:134:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  134 |     for(len=1;len<=s.size();len++)
      |               ~~~^~~~~~~~~~
/in/foo.cc:137:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  137 |        for(i=0;i<s.size();++i)
      |                ~^~~~~~~~~
/in/foo.cc:139:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  139 |        if(i>=s.size()) break;
      |           ~^~~~~~~~~~