/in/foo.cc: In function 'int main()':
/in/foo.cc:81:30: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::vector<unsigned int>::size_type {aka long unsigned int}' [-Wformat=]
  printf( "%d\n", num2.size() );
                              ^
/in/foo.cc:84:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for ( j = 0; j < num2.size(); ++j )
                ~~^~~~~~~~~~~~~