I've looked at that before, but I still don't see how it could make the program better?
Then you probably are not going to get any better as a programmer.

I need to get entire strings from the file I am writing to
Getting strings from files is an absolute doddle - If you browsed the C++ reference pages or 'how do i' links i gave you - read the examples and maybe, shock horror even tried them - then you would very soon see that.

So you want to get a string from a file that already has content and then write back to that same file?

Or you mean you want to just read from a data file and then write back to another file?

Either way you will see it is not hard - if you take time to learn.

Also how could different file types help and how do I use them?
Believe me anything other than a simple text file is not going to help you at the point you are now - If you can't get that how can you expect to work with files that are written to, data content created as a result of complex algorithms or something like that? that you need to have code to reinterpret back out in order to view? there is no 'filetype' that gives some kind of magic i/o fix.