There’s a challenge called “Explain these! Post in the community forum” where you explain the basic things you’ve learnt. I don’t expect anyone to reply or read this, it’s just for me I guess.
So the preprocessor directive from what I understand allows you to include other people’s code? Not 100% sure on this one, may be wrong, but I think it allows you to include what other people have made, kind of like extensions in chrome or something like that, this hasn’t been focused on yet.
Expression statements so far have been used to print something but that’s not their exclusive purpose from what I understand. They just state various things.
Declaration statements are where you put your variables and declare various sort of rules in the code that will run, again all it’s been used for is variables but I imagine you can do a lot more with it.
Then you have the main function which is required for everything to run and everything has to be in it.
Again I’m sure I’m very wrong and limited in understanding.