Hi

I've seen in many places the following code (or similar) to display
the nth number in the fibonacci sequence via recursion:

public class fibonacci
{
   static int fib(int n)
   {
       if (n==0||n==1) return 1;
       else {
           return fib(n-1)+fib(n-2);
    }
   }
   public static void main(String[] args)
   {
       System.out.print(fib(Integer.parseInt(args[0])));
   }
}

It's obviously a basic piece of code, but what I'm struggling to
understand is exactly HOW it returns the correct number. I guess this
is the key line:

return fib(n-1)+fib(n-2);

I understand the underlying principle for determining the correct
number in the sequence and obviously I can see that if the input is 0
or 1 then 1 is returned, but if I enter, say, 6, how does this class
actually return 13? Can anyone show me a step-by-step of what is
happening in the recursive function?

Sorry, I realise this is a lame question, but I'd really like to get
my head round it and I'd be grateful for any insight!

thanks
warren