/in/foo.cc: In function 'int main()':
/in/foo.cc:17:16: error: unable to find numeric literal operator 'operator""y'
  for(int i=1;i<0y;i++){
                ^~
/in/foo.cc:17:16: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes