foo.cc: In function ‘int main()’:
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=0; i<n.size(); i++) {
      |                      ~^~~~~~~~~
foo.cc:14:31: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   14 |                 for(int i=0; i<n.size()-1; i++) {
      |                              ~^~~~~~~~~~~
foo.cc:20:23: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   20 |         for(int i=0; i<n.size(); i++) {
      |                      ~^~~~~~~~~