Compilare: user.c:2:19: warning: return type defaults to ‘int’ [enabled by default] long long p,k,i,n;main(){freopen("fact.in","r",stdin);freopen("fact.out","w",stdout);scanf("%lld",&p);if(!p){printf("1");return 0;} ^ user.c: In function ‘main’: user.c:2:33: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] long long p,k,i,n;main(){freopen("fact.in","r",stdin);freopen("fact.out","w",stdout);scanf("%lld",&p);if(!p){printf("1");return 0;} ^ user.c:2:62: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] long long p,k,i,n;main(){freopen("fact.in","r",stdin);freopen("fact.out","w",stdout);scanf("%lld",&p);if(!p){printf("1");return 0;} ^ user.c:2:91: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] long long p,k,i,n;main(){freopen("fact.in","r",stdin);freopen("fact.out","w",stdout);scanf("%lld",&p);if(!p){printf("1");return 0;} ^