Compilare: user.c: In function ‘main’: user.c:14:17: warning: unused variable ‘u’ [-Wunused-variable] long p,k=0,n=1,u=1; ^ user.c:14:9: warning: unused variable ‘k’ [-Wunused-variable] long p,k=0,n=1,u=1; ^ user.c:15:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("factorial.in","r",stdin); ^ user.c:16:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("factorial.out","w",stdout); ^ user.c:17:7: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld",&p); ^