Please read the documentation for both opendir and readdir before you continue. Please.

You need to use opendir first. If that succeeds, you can use readdir on the directory handle.

If you have trouble understanding what the documentation says, please feel free to ask questions... but it looks like you're randomly changing your code without understanding what you're doing (or understanding the advice people give you), and it's really frustrating to try to help you. Please help yourself and please, please help us help you.

You're not using readdir properly.

That you can't understand readdir shows that you have special learning needs I'm not qualified and/or not willing to spend the time to address, especially not using this medium. Sorry. I'll happily point you in the right direction as I did in this thread if you so desire, but I won't write your code for you.