foo.cpp: In function 'bool cmp(const node&, const node&)':
foo.cpp:85:11: error: request for member 'x' in 'a', which is of non-class type 'node [200005]'
  return a.x.a*y.b<y.a*x.b;
           ^
foo.cpp:86:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^