Compilare: user.c: In function ‘read’: user.c:16:13: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen(FIN, "r", stdin); ^ user.c:18:11: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.c:20:34: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] for(i = 0; i < n; i++) scanf("%d", &arr[ i ]); ^ user.c: In function ‘_qsort’: user.c:57:1: warning: control reaches end of non-void function [-Wreturn-type] }; ^ user.c: In function ‘write’: user.c:68:11: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT, "w", stdout); ^