simple question about double precision

General Discussion Other

watchwrk

simple question about double precision

in General Discussion • Other • 3 years ago

The following code:

double x = 0.1;

println(x);

causes a display of the following value:

0.10000000149011612

Does anyone know what's causing the "149011612"? Is it a problem with println()? Is there any way to specify values to high precision?

any help much appreciated,

~Patch

Replies(3)

andreas.g..

Re: simple question about double precision

3 years ago

Processing automatically converts 0.1 to 0.1f (float).

To have double precision you could use:

double x = 0.1d;

But this answers only half of the question…

The other half can be found here:

http://mindprod.com/jgloss/floatingpoint.html

watchwrk

Re: Re: simple question about double precision

3 years ago

The weblink is great- thanks! However, the code you suggested doesn't seem to work. This line

double x = 0.1d;

causes an error message which reads: syntax error on token "f", delete this token

any ideas?

thanks,

~Patch

PhiLho

Re: simple question about double precision

3 years ago

Processing appends automatically a f after every number with decimal point it sees. Ie. it makes them float by default, without the constraint to add this prefix manually. But it doesn't mix well with the d notation...
Just drop the d, the number will be automatically be converted to double anyway.
You can use this notation in a .java file too.