View Single Post
  #3   Report Post  
Posted to microsoft.public.excel,microsoft.public.excel.misc
danieldc danieldc is offline
external usenet poster
 
Posts: 6
Default Sum - Sum < Zero ??? How is it? Bug in Excel formula?

On 12 abr, 07:41, "Harlan Grove" wrote:

Anyone with any experience in numeric programming is aware of it.


Yes, I tried it in Delphi using double variables and the values
(115.00 , 113.20 , 1.80) and also got the same result (-2.88658E-15).
Of course, if I was to make a program, and not a excel worksheet, I
would use Currency or Longint types (this last divided or multiplied
by 100), or if going to use real/float types, all the time ensure the
correct round() or trunc() functions.

But this post I included not to talk about programming language or
advanced computation.

I'was with a problem using Excel: some numbers, 2 digit precision,
after sum and subtraction, results different from zero, where the only
value expected was zero.

And now, searching this forum, I found other posts about this same
affair.


You could always use the Precision As Displayed option, but it causes
other problems. But Excel provides ONLY two options in this regard:
IEEE double precision reals (basically Excel's 15 decimal digit
precision reals) and fixed point (Precision As Displayed). Choose the
one you want.


I tried it but didn't get the results. As the final user could change
that option, it was better to lost some milliseconds at more trunc()
functions.


Thanks,
Daniel