Login [Register]
Don't have an account? Register now to chat, post, use our tools, and much more.
So a little while back, there was some discussion about implementing recursion in TI-BASIC; the entire thread just boiled down to concluding "yeah, even though you can call programs from within programs, there are no return values, so you have to implement your own version of a call stack". All-in-all, recursion is not particularly easy or useful.

But, there are some "exceptions"; take for example this factorial calculator:


:If N:prgmFACT

which handles the job quite nicely. It got me wondering if it was possible to accomplish the next step-up in recursive program examples, calculating the Fibonacci sequence, without a call stack or list of some kind; only real variables and Ans.

Well, it turns out you can:



Why does this work? Well, if you look at the call stack for your average recursive Fibonacci calculator, the number of total calls is actually 2F(n) - 1, for F(n) the nth Fibonacci number. Thus, we don't have to pass return values; just increment some counter every time make a call.

Is this efficient? Absolutely not. Is this adaptable to other recursive problems? Probably not, unless its a slight mathematical modification of the Fibonacci sequence. Is this cool? I think so; I like pushing TI-BASIC.
Register to Join the Conversation
Have your own thoughts to add to this or any other topic? Want to ask a question, offer a suggestion, share your own programs and projects, upload a file to the file archives, get help with calculator and computer programming, or simply chat with like-minded coders and tech and calculator enthusiasts via the site-wide AJAX SAX widget? Registration for a free Cemetech account only takes a minute.

» Go to Registration page
Page 1 of 1
» All times are GMT - 5 Hours
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum