/in/foo.cc: In member function 'void node::getnext()':
/in/foo.cc:45:7: warning: unused variable 'head' [-Wunused-variable]
   int head=0,tail=1,now=1;
       ^~~~
/in/foo.cc:45:14: warning: unused variable 'tail' [-Wunused-variable]
   int head=0,tail=1,now=1;
              ^~~~