/in/foo.cc: In function 'void div(int)':
/in/foo.cc:14:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<a.size();i++){
                     ~^~~~~~~~~
/in/foo.cc:20:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<r.size();i++)
                     ~^~~~~~~~~