Keyboard control by C++ application

Hello,
I am trying to find the way to have the total control on the computer keyboard. I want to change the values in output once you press a key.
I would like to create an application in c++ to make it in runtime in the Windows OS.
Any suggestions?

Thanks.

Real

You’ll need to write a device driver, as Windows doesn’t permit application-level code to interact this way with other processes.

Oh really thanks @fire-eggs thank you to having given your advice, I’ll try to go deep in this drive way. Regards.