/in/foo.cc: In function 'int main()':
/in/foo.cc:42:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i=0;i<v.size();i++) printf("%d%c",v[i],i==v.size()-1?'\n':' ');
               ~^~~~~~~~~
/in/foo.cc:42:51: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i=0;i<v.size();i++) printf("%d%c",v[i],i==v.size()-1?'\n':' ');
                                                  ~^~~~~~~~~~~~