/in/foo.cc: In function 'int main()':
/in/foo.cc:31:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |     for(int i=1;i<c.size();i++){
      |                 ~^~~~~~~~~