Compilare: user.cpp: In function ‘int main()’: user.cpp:17:33: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 2 has type ‘int’ [-Wformat=] printf("%lld\n",(2*x*phi[x])); ^ user.cpp:5:6: warning: unused variable ‘n’ [-Wunused-variable] {int n,i,j,t,x; ^ user.cpp:6:28: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sum.in","r",stdin); ^ user.cpp:7:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^ user.cpp:8:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sum.out","w",stdout); ^ user.cpp:16:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^