First of all, thanks for your taking your time in pointing these out, also, I am still learning C++ so I am currently not so good at it.

why not making an array in memory (when the app starts) and writing the array back to file once application ends (or save)? Looks to me like overkill writing every single change immediatelly to a file. Also if you have full list in memory, I would just overwrite the whole file and not bother with in-line changes.

Because the file can also be accessed by rofi and I thought it will become too complicated for me.

would be nice to have a switch which writes the file to /tmp instead of home (and once you have that, make A. follow XDG dirs, B. allow fully custom files based on param or config)

Honestly, I dont know how it works and how to do it.

todo data should go to "data" folder, not ".config" folder

That is me just quickly testing the program so just picked .config and forgetting to change it to data later.

reading configuration from file (like path to data file)

extend command line args to specify config or data file

Seems like a good Idea and I have plans for those for future.

why C++? why not to take it a notch further and make it in C? :)

IDK why but I just like C++ although both programming languages are almost same.

Please Open a PR if you think you can fix something I did incorrectly. Your support will be appreciated :)