Here's what you should be able to to in order to follow the C++ course.
Use a plain text editor, not an IDE.
Spoiler alert: no.
Installing g++ on Ubuntu 2020 LTS 'Focal Fossa' is extremely easy.
From PPA(?), from source, or cut corners by sneaky copying.
Good for you. We know a few things, but no demo (sorry), because we'd have to pay Apple to make one.
Windows is the hardest to fix. And you have to choose from multiple options.
First choice: between either another (virtual) computer, or a glue layer.
More choice: another computer could be a cheap old laptop, a RaspBerry Pi, or a virtual machine.
Installing Ubuntu on real hardware works the same. Installing VirtualBox itself isn't part of the demo.
Also check out how to share files from the host with the guest OS. so you can edit in Windows but compile under Linux.
I couldn't show the Windows example because that VirtualBox is actually running on Linux (of course).
Second choice: a light or a heavy glue layer. MinGW-w64 is the lightest.
Not perfect for the C++ course, but certainly less resource-hungry than VirtualBox. And no extra hadware needed.