Compilare: user.cpp: In function ‘long long unsigned int ndiv(long long int, long long int&)’: user.cpp:17:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(p[i]*p[i]<=x && i<=z) ^ user.cpp:26:13: warning: the address of ‘p’ will always evaluate as ‘true’ [-Waddress] if(p) ^ user.cpp:14:31: warning: unused variable ‘s’ [-Wunused-variable] unsigned long long i,nr,e,s,sum=1; ^ user.cpp: In function ‘int main()’: user.cpp:44:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1; i<=n; i++) ^