Compilare: main.cpp: In function 'int main()': main.cpp:19:10: warning: iteration 749998 invokes undefined behavior [-Waggressive-loop-optimizations] v[i] = 1; ~~~~~^~~ main.cpp:6:35: note: within this loop #define rep(a,b,c,d) for(a = b; a <= c; a += d) ^ main.cpp:18:3: note: in expansion of macro 'rep' rep(i,4,nmax,2) ^~~ main.cpp:32:15: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized] fout << a * a; ^