Compilare: user.cpp: In function ‘int main()’: user.cpp:4:287: warning: operation on ‘i’ may be undefined [-Wsequence-point] using namespace std;ofstream g("sortaret.out");int x,m,n,y,d[t],i;vector<int>a[t];bool w[t];void D(int x){w[x]=1;for(int i=0;i<d[x];++i){if(!w[a[x][i]])D(a[x][i]);}g<<x<<" ";}int main(){ifstream f("sortaret.in");f>>n>>m;for(;m--;)f>>x>>y,a[y].push_back(x);i=n;for(;i;)d[i]=a[i--].size();for(;i<n;)if(!w[++i])D(i);} ^