Compilare: user.cpp: In function ‘int n(int)’: user.cpp:6:13: warning: unused variable ‘t’ [-Wunused-variable] int i=5,t=0,k=0; ^ user.cpp: In function ‘int main()’: user.cpp:16:33: 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:17:35: 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); ^