Compilare: user.cpp: In function ‘int main()’: user.cpp:20:13: warning: unused variable ‘i’ [-Wunused-variable] int n,p,i; ^ user.cpp: In function ‘long long int f(long long int, long long int)’: user.cpp:15:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:18:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lgput.in","r",stdin); ^ user.cpp:19:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lgput.out","w",stdout); ^ user.cpp:21:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&p); ^