How to execute the above programs?
To execute the above programs you need to install Node.js software. From nodejs.org you can get installers for several operating systems.
The last command above works only if the Path environment variable is set so that node.exe can be activated. Running programs in the Command Prompt Window is not so difficult when you remember that commands can be repeated with the Arrow-Up and Arrow-Down keys. All the above programs have been developed so that I have written them with the free Notepad++ editor and then executed them with commands such as the one above.
Links to videos about the very basics:
Links to videos about object-oriented programming: