In that case you'll need what are called dynamic arrays...
Which means you have to define the variables you want to save yourself
You have to get to know malloc,realloc functions, as well as sizeof.
It'd be hard to explain the whole thing at the moment, because it's tricky coding, and though I know it, I haven't practiced it nearly enough to explain it well. I suggest looking up the functions in searches, as well as dynamic arrays... Look through examples, and then follow a similar approach as I've explained just before.
Then of course you can't save it in groups, so, you'll also need to know how to open a file for reading, writing, and you'll need to know how to save to it, and close it... That's not that easy, and I suggest doing it with text files at the moment, because it's simple. fopen, fclose, fgets, fprintf these are the more important functions to know, again I suggest looking them up, and getting to know them... That's all I can say, because I can't explain it well enough... sorry, but I hope this'll still be helpful!
