• =?UTF-8?B?Tm9yZGzDtnc=?= (1/1) Jan 17 2017 What's the easiest way to print a double in maximum precision?
• pineapple (5/6) Jan 17 2017 https://github.com/pineapplemachine/mach.d/blob/master/mach/text/numeric...
• Nicholas Wilson (2/8) Jan 17 2017 Alternatively use %a to print in hex to verify exact bit patterns.
• kinke (3/5) Jan 18 2017 +1, if it doesn't have to be human-readable.
• Basile B. (11/12) Jan 17 2017 %.6g for floats and %.17g for doubles. This is for example what's

=?UTF-8?B?Tm9yZGzDtnc=?= <per.nordlow gmail.com> writes:

What's the easiest way to print a double in maximum precision?

pineapple <meapineapple gmail.com> writes:

On Wednesday, 18 January 2017 at 00:09:42 UTC, Nordlöw wrote:
 What's the easiest way to print a double in maximum precision?

https://github.com/pineapplemachine/mach.d/blob/master/mach/text/numeric/floats.d#L60

You can also try the formatting directive "%.20f" but unlike the 
former I can't offer any guarantees of its accuracy (it's 
probably accurate)

Nicholas Wilson <iamthewilsonator hotmail.com> writes:

On Wednesday, 18 January 2017 at 00:23:37 UTC, pineapple wrote:
 On Wednesday, 18 January 2017 at 00:09:42 UTC, Nordlöw wrote:
 What's the easiest way to print a double in maximum precision?

 https://github.com/pineapplemachine/mach.d/blob/master/mach/text/numeric/floats.d#L60

 You can also try the formatting directive "%.20f" but unlike 
 the former I can't offer any guarantees of its accuracy (it's 
 probably accurate)

Alternatively use %a to print in hex to verify exact bit patterns.

kinke <noone nowhere.com> writes:

On Wednesday, 18 January 2017 at 03:36:39 UTC, Nicholas Wilson 
wrote:
 Alternatively use %a to print in hex to verify exact bit 
 patterns.

+1, if it doesn't have to be human-readable.

Basile B. <b2.temp gmx.com> writes:

On Wednesday, 18 January 2017 at 00:09:42 UTC, Nordlöw wrote:
 What's the easiest way to print a double in maximum precision?

%.6g for floats and %.17g for doubles. This is for example what's 
used on std.json to get a perfect conversion from string to 
value. the number is the maximum number of digits in the 
fractional part.

6 and 17 are rounded, real values can be found  here 
(https://en.wikipedia.org/wiki/Floating_point#Internal_representation)

see also:



and this

https://github.com/dlang/phobos/pull/4343#issuecomment-220810593