Compilare: user.cpp: In function ‘int main()’: user.cpp:6:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fact.in","r",stdin); ^ user.cpp:7:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fact.out","w",stdout); ^ user.cpp:27:6: warning: ‘s’ may be used uninitialized in this function [-Wmaybe-uninitialized] else if(s!=x)cout<<-1; ^ user.cpp:29:8: warning: ‘n’ may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<n; ^