Compilare: main.cpp: In function 'int main()': main.cpp:43:25: warning: unused variable 'w' [-Wunused-variable] long long int n, k, w, m=0; ^ main.cpp:43:28: warning: unused variable 'm' [-Wunused-variable] long long int n, k, w, m=0; ^ main.cpp:46:11: warning: iteration 1000004 invokes undefined behavior [-Waggressive-loop-optimizations] fac[i]=prod(fac[i-1], i); ~~~~~~^~~~~~~~~~~~~~~~~~ main.cpp:45:20: note: within this loop for (int i=1; i<=nmax; i++) ~^~~~~~