/in/foo.c: In function 'sum':
/in/foo.c:23:6: warning: variable 'temp' set but not used [-Wunused-but-set-variable]
  int temp;
      ^~~~
/in/foo.c: In function 'main':
/in/foo.c:38:53: warning: variable 'temp' set but not used [-Wunused-but-set-variable]
   int data[MAXN], head, tail, n, i, total1, total2, temp;
                                                     ^~~~
/in/foo.c:38:37: warning: variable 'total1' set but not used [-Wunused-but-set-variable]
   int data[MAXN], head, tail, n, i, total1, total2, temp;
                                     ^~~~~~
/in/foo.c: In function 'sum':
/in/foo.c:34:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^