Can anyone help me with this? A glitch appeared when running a TI-Basic program on an 84+CSE, and it had always run successfully before. In a For( loop the index variable kept resetting to 0, although no code referenced that variable: it was just a count of how many times the loop should run. Lots of other things took place in the loop, however, so I ended up adding loads of instructions to display the value of the variable at various points so I could track down when it went wrong. The conclusion made no sense, but prompted me to write these test programs:

Code:

This one prints 1, then repeatedly 0 until I hit ON: the loop can never end.

Next I tried,

Code:

which displays digits 1-5 down the right of the Home Screen, as it should. So ClrDraw by itself did not set R to 0.

Then

Code:

which is apparently the same as the previous one, except for alternately visiting the [blank] Graph Screen and the Home Screen, but now displays an endless sequence of 0s on the Home Screen, until I Break.

Next I try

Code:

where the loop "works", showing that ClrDraw is required for this fault to occur.

Then finally,

Code:

which is the same as the first program here, but with a different name for the variable. This displays the digits 1 - 5 successively on the Graph Screen.
So in the main program I was originally debugging, I altered the index variable from R to S, and it now works properly. But none of this makes sense to me: what is going on?
Footnote: None of these test programs is running from Archive, and I have no evidence to associate this with any Doors CSE issues.

I'm not equipped to do any testing of my own at the moment, but I suspect your problem stems from the system implicitly using some variables internally when doing graph operations.

If you're in polar mode, modifying the graph will probably modify R and θ; using ClrDraw presumably resets both to zero. I suspect you'd see similar behavior with X and Y in function graphing mode.

Thanks, you solved it! I feel so stupid wasting over an hour being puzzled by that, and not noticing I was in Polar mode. I knew the program had run many times before without that fault.