1 int data[] = {1,2,3,4,5,6,7,8,9}; 2 Map<RowVectorXi> v(data,4); 3 cout << "The mapped vector v is: " << v << "\n"; 4 new (&v) Map<RowVectorXi>(data+4,5); 5 cout << "Now v is: " << v << "\n";