Quoting (part of) a msg from you of 08 Nov 1994:

 RB> I need to do a distance calculation between two points
 RB> (x0,z0) and (x1,z1).  The way I know to do this is to use
 RB> the distance formula, but it requires a square root
 RB> calculation.  I don't want to use the standard C sqrt()
 RB> function because I am not using floating point for anything
 RB> else.

Rob,

If you are going to use the mentioned Newton Raphson method (and why not),
then it helps if the first appromimation is as close as possible with a
simple calculation. Since you basically need the hypothenuse of a
right-angled triangle, you know the limits of the result. If we call the
sides 'a' and 'b' and the hypothenuse 'c' then: 
 - c  greater than max(a,b) 
 - c  shorter than sqrt(2) * (a+b)/2   . . .  (maximum if  a==b)
So a good approximation-formula seems to be:  (a+b) * 3 / 5

And as reaction to the arguments about floating-point support being
'standard' in OS/2, I would say: If the co-ordinates and the result have to
be integer-values, you need 3 type conversions for every calculation. This
might be more resource consuming than the integer approximation itself! 
You would have to write a small 'benchmark'-program to verify this.
   
Cheers, Rob 
--- timEd/2 1.01+