Compilare: user.cpp: In function ‘int main()’: user.cpp:7:10: warning: unused variable ‘x’ [-Wunused-variable] int n,i,x,k,q; ^ user.cpp:7:12: warning: unused variable ‘k’ [-Wunused-variable] int n,i,x,k,q; ^ user.cpp:7:14: warning: unused variable ‘q’ [-Wunused-variable] int n,i,x,k,q; ^ cc1plus: warning: iteration 400000u invokes undefined behavior [-Waggressive-loop-optimizations] user.cpp:27:2: note: containing loop for(i=0;i<=400001;i++) ^