Compilare: user.cpp: In function ‘int main()’: user.cpp:9:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("flori4.in","r",stdin); ^ user.cpp:10:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("flori4.out","w",stdout); ^ user.cpp:11:5: warning: ‘n’ is used uninitialized in this function [-Wuninitialized] for(i=3;i<=n;i++) ^ user.cpp:17:11: warning: ‘fn’ may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<fn<<'\n'; ^