Compilare: user.c: In function ‘_sw’: user.c:39:6: warning: type of ‘a’ defaults to ‘int’ [enabled by default] void _sw(a, b) { ^ user.c:39:6: warning: type of ‘b’ defaults to ‘int’ [enabled by default] user.c: In function ‘read’: user.c:18:13: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen(FIN, "r", stdin); ^ user.c:20:11: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.c:22:34: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] for(i = 0; i < n; i++) scanf("%d", &vec[ i ]); ^ user.c: In function ‘write’: user.c:31:13: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT, "w", stdout); ^