This is my second program I wrote for TI-89. Can someone who thinks that knows TI-BASIC well, takes a quick look.

Please make some comment. Tell me what is good and what should I change to make this faster, more efficient or simply not so complicated.

Thanks


Program takes input from user, and calculates some equations stored in global variables, that are dependent on x and y coordinates.

User can than choose to input some points (up to 6 for each equation) and get results in those points.


Code:

The only thing that (immediately) stands out to me is your use of Lbl and Goto. The 89 has much better ways to jump around a program than them: their use is generally discouraged for almost everything (except 83+ Basic where they are sometimes the only option). For instance, you can define a subroutine like so:


Code:


And then you can call it using subprgm() from inside your program. You can also define functions and have them return values. For more information on how to make subprograms see this page in particular.

That would probably make it easier to read, if not necessarily more efficient.

Unfortunately the 68k section of TI-Basic Developer is less fleshed out compared to the 83+ one, but it's still a useful resource (if you weren't already aware of it).

Thanks for replay.

I thought of subroutines and in the next program i will probably use them.
The "problem" with subroutines is that no local variable form lets call it main program, can't be recognized in a subroutine and vice versa. Solution is probably to work in maybe just temporary separate folder, with everything stored in global variables that are deleted on exit.

Or is there some better way?

You can pass arguments to the subroutine just like you can pass arguments to a "main" program or function:


Code:


And as I said, you can use Return to return a value to whatever called the function.

But if you need to return multiple variables, I think you either have to return a list or do what you described.

Most programming languages let you return a list or structure from a subroutine in order to do what you're describing, although the ones that I'm thinking of that give the programmer the most flexibility, namely PHP and Python, allow mixed-type lists. TI-68k-BASIC, of course, does not.

Edit: I've been informed that my 68k BASIC is horribly rusty, and that you can in fact have mixed-type lists. Huzzah!

Actually, 68k Basic does have multi-typed lists- {1, 2, "abc"} is a perfectly valid list.

Well, actually, there is a "data" object that you can store whatever you want in, either in one or two dimensions. There are matrix and list objects as well, which are about the same as their z80 equivalents.

And, Kerm just edited his post as I was writing this one.

So using subprograms and returning values is good programming practice.

I'll probably rewrite my program for practice and and paste the code here so somebody can comment it.

Thanks