How to auto update c++ program?

Question

Programming

Tell me how to make an auto-update system for the program? Or give ready-made code, but it's better to explain in detail.
There is a site, there is a folder on the site where the files are located: - version.txt
"The file says 0.0.2"
- Launcher.exe
the message "Update the program, forcibly" pops up, while preventing you from using it further, then when you click on ok, so that the program itself downloads Launcher.exe, and replaces the place of the old one, and then starts.
-------------------------------------------------- ------------------------------
А да еще хотел спросить вот написал программу скомпилировал в exe, передаю через интернет другим людям они скачивают и антивирусы у них ругаются что программа троян.

Answer 1

"How to make sure that when the program starts, versions are automatically compared without downloading version.txt, and if the versions do not match, the message "Update the program, forcibly" pops up, while not allowing it to continue to be used, then when you click on ok, what would the program itself downloaded Launcher.exe, and replaced the place of the old one, and then it started."
Add an API to the site to display the current version in a convenient format.
Add a call to your site for a new version to the launch of the program.
Add a ban on further use to the program launch if it is known that there is a new version.
Add to the program the message "Update the program" with the OK button, which will download and run Launcher.exe, which will update the old program and run it.
Все просто.