On Saturday, 9 February 2019 at 04:30:22 UTC, DanielG wrote:
On Saturday, 9 February 2019 at 03:33:13 UTC, Murilo wrote:
Thanks but here is the situation, I use printf("%.20f", 0.1);
in both C and D, C returns 0.10000000000000000555 whereas D
returns 0.10000000000000001000. So I understand your point, D
rounds off more, but that causes loss of precision, isn't that
something bad if you are working with math and physics for
example?
0.1 in floating point is actually 0.100000001490116119384765625
behind the scenes.
So why is it important that it displays as:
0.10000000000000000555
versus
0.10000000000000001000
?
*Technically* the D version has less error, relative to the
internal binary representation. Since there's no exact way of
representing 0.1 in floating point, the computer has no way of
knowing you really mean "0.1 decimal". If the accuracy is that
important to you, you'll probably have to look into
software-only number representations, for arbitrary decimal
precision (I've not explored them in D, but other languages
have things like "BigDecimal" data types)
Thank you very much for clearing this up. But how do I make D
behave just like C? Is there a way to do that?
