Compilare: main.cpp: In function 'int main()': main.cpp:17:21: warning: iteration 999998 invokes undefined behavior [-Waggressive-loop-optimizations] 17 | ciur[i * 2] = 1; | ~~~~~~~~~~~~^~~ main.cpp:16:23: note: within this loop 16 | for (int i = 2; i <= 1000000; i++) | ~~^~~~~~~~~~ main.cpp:19:20: warning: iteration 1999997 invokes undefined behavior [-Waggressive-loop-optimizations] 19 | if (!ciur[i]) | ~~~~~~^ main.cpp:18:23: note: within this loop 18 | for (int i = 3; i <= 2000000; i++) | ~~^~~~~~~~~~