How to create a 2 programs (one for server-side in smart phone for remote controlling, one for client-side in laptop )?

Question

I mean, smart phone will act as a controller and will manipulate the computer, what concepts do I need to learn to create something like this?
What I mean by manipulation is that i need to be able to create some text files and read onto etc. via smart phone.
Also which language I will need?

Answer 1

Without programming anything, you could run a VNC Server on your laptop and connect to it from a VNC client on your smart phone.
https://www.realvnc.com/en/connect/download/viewer/

That will give you control on your smart-phone's touch screen to your laptop.

If your laptop uses Windows and your phone uses Android, https://www.youtube.com/watch?v=kt8CthKsA5U shows how to control it using Remote Desktop.

If you really feel the urge to program something for this, you could write a web application that is hosted on your laptop, connect to it from your smart phone's web browser, and through your web application, control files on your laptop. Just program the server to read and write files as the user interacts.
One idea is you have a single page with a big textarea representing content of a file. On posting the form, replace content in a specific file. With every page refresh, fill the textarea with text from the same file.

Any web development-capable programming language would work for making this web application. PHP is likely the easiest to install and make the application if you haven't made a web app before. You could install WAMP or XAMPP on your laptop and make it accessible over local area network. https://www.youtube.com/watch?v=4UwbSCVgVas shows how. Then do a little web development so your app reads and writes a file on your laptop as you like.

Running a server on your phone is a little awkward and definitely not necessary. I recommend running the server on your laptop, connecting your phone to the same wifi network, and the phone use a browser.