/in/foo.cc: In function 'int main()':
/in/foo.cc:34:21: warning: 'b.node::y' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<b.x<<"  "<<b.y<<endl;
                     ^
/in/foo.cc:34:13: warning: 'b.node::x' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<b.x<<"  "<<b.y<<endl;
             ^~~~