/in/foo.c:13:34: error: parameter 2 ('b') has incomplete type
 int cmp(const void *a,const void b)
                                  ^
/in/foo.c: In function 'cmp':
/in/foo.c:15:56: error: '(struct student *)a' is a pointer; did you mean to use '->'?
 return ((struct student )b).money-((struct student *)a).money;
                                                        ^
                                                        ->
/in/foo.c:16:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^