Compilare: main.cpp: In function 'void sieve()': main.cpp:11:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation] for (int i = 4; i <= nmax; i += 2) ^~~ main.cpp:13:9: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for' p[++k] = 2; ^ main.cpp:15:20: warning: iteration 500001 invokes undefined behavior [-Waggressive-loop-optimizations] if (!ciur[i]) { ~~~~~~^ main.cpp:14:23: note: within this loop for (int i = 3; i <= nmax; i += 2) { ^