Programing question

[Anonymous]

What is the best bit of code to use to avoid "divide by zero" errors?
I run into this issue often when using circular functions
such as in the following piece of code.

ratio=b/a
ang=atn(ratio)

If "a" happens to be zero there is an error.
Usually I resort to placing the following at the
beginning of the script.

if a=0 then a=0.0000001

This "work-around" is logically very dissatisfying to me.
Is there a better way?

Thank you,
Peter Devlin

[Durval]

Instead of conditional change of 'a', why not simply change 'ang' directly?

IF a<epsilon THEN ang=90

Stuart, wouldn't this code
ratio = oA / ( (oB=0) * Epsilon + oB )
trigger the annoying 'precision problems' warning?

[Anonymous]

Durval;

I might be wrong, but IMHE, "x=0" doesn't seem to create a precision problem. x=1 (or any other number) can.

Will test a little over the w/e.

? - Stuart

[Oleg]

I would prefer:

IF ABS(a)<EPS THEN ang=SGN(b)*90 ELSE ang=TAN(b/a)

as imho it is more readable and clear

[Anonymous]

Hello,
Looking at all of the replies to my original question I can only conclude
that some conditional, somewhat arbitrary, change to the devisor must be made when the devisor acquires a zero value.
At the time I posted my question I was wondering if there was some mathematical algorithm or programing command that would say in effect
if a=0 then
a=(smallest non-zero quantity allowed by the program/math processor).
I was thinking that in floating point arithmetic "zero" must have some
internal definition limited by precision.
Since I don't have a computer science background the above statements
may be complete gibberish.
This thread has certainly brought up some fascinating issues.
Thank you all for your comments,
Peter Devlin