# Talk:Not a Number

**--manus 19:37, 8 May 2007 (CEST)**: Have a look at Real Numbers page where we already started a similar discussion but currently only for the specification of REAL_64, not its usage.

## One possibility for working with NaN

I was working on a project to represent complex numbers and used the following `is_equal' to accomodate the use of NaNs:

is_equal (other: like Current): BOOLEAN
-- Is `other' attached to an object considered
-- equal to current object?
-- If current object is not a number (NaN) and
-- `other' is as well `True' will be returned.
do
if is_nan then
if real /~ real and then imaginary ~ imaginary then
Result := real /~ other.real and then imaginary ~ other.imaginary
elseif real ~ real and then imaginary /~ imaginary then
Result := real ~ other.real and then imaginary /~ other.imaginary
elseif real /~ real and then imaginary /~ imaginary then
Result := real /~ other.real and then imaginary /~ other.imaginary
end
else
Result := real ~ other.real and then imaginary ~ other.imaginary
end
end

--Colin-adams 10:17, 22 February 2010 (UTC) Can you format that code? I can't follow it at all as it stands.