Compilare: user.c: In function ‘main’: user.c:37:5: warning: passing argument 4 of ‘qsort’ from incompatible pointer type [enabled by default] qsort(graf,m,sizeof(muchie),&cmp); ^ In file included from user.c:1:0: /usr/include/stdlib.h:756:13: note: expected ‘__compar_fn_t’ but argument is of type ‘int (*)(struct muchie, struct muchie)’ extern void qsort (void *__base, size_t __nmemb, size_t __size, ^ user.c:39:9: warning: variable ‘c’ set but not used [-Wunused-but-set-variable] int c[200000]; ^