This is my first post here in the CodeGuru Forums, and I'm still a newbie to coding and programming.
Sometimes, I bump against a software or program, and don't understand how a part of it (or the entire software) works. So, I thought whether it might be possible to "Decompile" a program to get its source code, just like you would do on a webpage. Is it possible to be done at all? Is there any software designed for that purpose? If not, how can I build one?

Thanks in advance,