The provided code is not a template. The code is just a "help" to the design of base classes. It is nor the best code possible or the most simple one. It has been crippled and censored so many parts will not work as expected.
It compiles but IT DOES NOT WORK ON PURPOSE.
We suggest you take a look, get inspired, and extend and fix it if you want. If not, it is very often much faster to develop your own and make your own implementation.
This assignment does not have only one solution, many interpretations are valid as long as they reflect the course teaching.
REMEMBER: IT IS NOT TO BE FILLED OR KEPT IF YOU DO NOT WANT IT or DO NOT THINK IT IS A HELP.