Compilare: user.c:22:1: warning: return type defaults to ‘int’ [enabled by default] main() { ^ user.c: In function ‘getN’: user.c:20:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.c: In function ‘main’: user.c:23:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("fact.in", "r", stdin); ^ user.c:24:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("fact.out", "w", stdout); ^ user.c:28:7: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &p); ^