Compilare: user.c: In function ‘main’: user.c:27:5: warning: passing argument 4 of ‘qsort’ from incompatible pointer type [enabled by default] qsort(idx, n, sizeof(int), MyComp); ^ In file included from user.c:2:0: /usr/include/stdlib.h:761:13: note: expected ‘__compar_fn_t’ but argument is of type ‘int (*)(void *, void *)’ extern void qsort (void *__base, size_t __nmemb, size_t __size, ^ user.c:14:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("algsort.in", "r", stdin); ^ user.c:15:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("algsort.out", "w", stdout); ^ user.c:18:20: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] int n, i; scanf("%d", &n); ^ user.c:20:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &arr[i]); ^