Implement a Buffer template class. The buffer stores elements
...Background
The Corona Institute, which is engaged in vital medical research, wishes to monitor and control access to the rooms and labs in its research division. This facility has a number of rooms connected by doors. Due to "social distancing" the doors are one-way only, providing a link FROM one room TO another. All rooms also have an emergency one-way door to the Outside, which can be used at any time. The doors are controlled by inserting a "Pass" into a pass reader which controls whether the doors will open to let staff through to the room on the other side, or not.