Sinclair ZX80 / ZX81 / Z88 Forums

Currently playing about with my ZX80.
What's the best way to program it to draw a circle?
Might sound very basic but that's where i'm at!

Try this and let us know how it goes:

10 FOR ANGLE = 0 TO 360 STEP 5
20 LET X = RND * 10 * SIN(ANGLE)
30 LET Y = RND * 10 * COS(ANGLE)
40 PLOT 96 + INT(X), 48 + INT(Y)
50 NEXT ANGLE

I doubt it can work.
ZX80 only uses integer math, no trigonometry, no PLOT.
Hence the question and why there was no answer.
It's far from easy if you want to calculate it.
Of course you can take a circle , convert the content to ZX80 string and print it.
But that's a solution to a different question
Or change the ZX80 ROM to a ZX81 ROM

The above works with the ZX81 only. My mistake: the ZX80 only supports integers, and to create a circle, you must work with decimal numbers.

Yes, the lack of trigonometry functions and floating point numbers makes it a tad more difficult compared to the ZX81 ROM…

Mark

This uses integer math.

https://www.sinclairzxworld.com/viewtop ... les#p48543