/in/foo.cc: In function 'int main()':
/in/foo.cc:7:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    7 |         for (int i=2;i<=s.size()-1;i++)
      |                      ~^~~~~~~~~~~~
/in/foo.cc:9:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |                 for (int j=0;j<=s.size()-1;i++)
      |                              ~^~~~~~~~~~~~