Because 0.01 = 1/(2*2*5*5) is a decimal not a binary fraction.

That means it can't be expressed without rounding error as a binary floating point number.(5 and 2 are different primes), pretty much like how you can't express 1/3 as a finite decimal floating point number without.

see also Humans have too many fingers and What Every Computer Scientist Should Know About Floating-Point Arithmetic

Cheers Rolf
(addicted to the Perl Programming Language and ☆☆☆☆ :)
Wikisyntax for the Monastery

In reply to Re: While loop with addition goes weird (binary float rounding error) by LanX
in thread While loop with addition goes weird by chiel

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