Compilare: main.cpp: In function 'int main()': main.cpp:2:132: warning: operation on 'j' may be undefined [-Wsequence-point] 2 | int main(){int64_t n,m=666013,d[m]{0,1},i=2,j;std::ifstream l("100m.in");std::ofstream o("100m.out");for(l>>n;i<=n;)for(j=i++;j;d[j--]=j*(d[j]+d[j-1])%m);for(;--i;j+=d[i]);o<<j%m;} | ~^~ main.cpp:2:132: warning: operation on 'j' may be undefined [-Wsequence-point] main.cpp:2:132: warning: operation on 'j' may be undefined [-Wsequence-point] main.cpp:2:132: warning: operation on 'j' may be undefined [-Wsequence-point] main.cpp:2:132: warning: operation on 'j' may be undefined [-Wsequence-point] main.cpp:2:132: warning: operation on 'j' may be undefined [-Wsequence-point]