Compilare: user.cpp: In function ‘int main()’: user.cpp:4:298: 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],v;bool w[t];void D(int x){w[x]=1;for(int i=0;i<d[x];){int y=a[x][i++];if(!w[y])D(y);}g<<x<<" ";++m;}int main(){ifstream f("sortaret.in");f>>n>>m;for(;m--;)f>>x>>y,a[x].push_back(y);++m;i=n;for(;i;)d[i]=a[i--].size();for(;i<n;)if(!w[++i])D(i);}//g<<v[--m]<<" ";} ^