Compilare: user.cpp: In function ‘void bt(int, int)’: user.cpp:24:19: warning: iteration 12 invokes undefined behavior [-Waggressive-loop-optimizations] if(prime[i]>ult && (prime[i]-ult)<=n) ~~~~~~~^ user.cpp:22:18: note: within this loop for(int i=1;i<=13;i++) ~^~~~ user.cpp: In function ‘int main()’: user.cpp:47:25: warning: iteration 12 invokes undefined behavior [-Waggressive-loop-optimizations] prim[prime[i]]=1; ~~~~~~~^ user.cpp:45:22: note: within this loop for(int i=1;i<=13;i++) ~^~~~