/in/foo.cc: In function 'Node* quchong(Node*)':
/in/foo.cc:45:16: warning: right operand of comma operator has no effect [-Wunused-value]
  delete p,prev,newp;
                ^~~~
/in/foo.cc:45:20: warning: right operand of comma operator has no effect [-Wunused-value]
  delete p,prev,newp;
                    ^