Compilare: user.c: In function ‘swap’: user.c:86:6: warning: type of ‘a’ defaults to ‘int’ [enabled by default] void swap(a, b) { ^ user.c:86:6: warning: type of ‘b’ defaults to ‘int’ [enabled by default] user.c: In function ‘read’: user.c:30:13: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen(FIN, "r", stdin); ^ user.c:32:11: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.c:34:34: 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 ‘write’: user.c:101:13: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT, "w", stdout); ^ user.c:103:11: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^