Exact integer-valued floats

[Paul Rubin]

Steven D'Aprano <steve+comp.lang.python at pearwood.info> writes:
> Have I got this right? Is there a way to work out the gap between one 
> float and the next?

Yes, 53-bit mantissa as people have mentioned.  That tells you what ints
can be exactly represented.  But, arithmetic in some situations can have
a 1-ulp error.  So I wonder if it's possible that if n is large enough,
you might have something like n+1==n even if the integers n and n+1 have
distinct floating point representations.