Re: [bug-gawk] How to print the just enough number digits so the machine representation of the number does not change?

[Eli Zaretskii]

> Date: Sun, 7 Oct 2012 22:39:30 -0500
> From: Peng Yu <address@hidden>
> The following "print" command only print 6 digits. I do not want to
> explicitly specify the number of digits. But I want to print just
> enough number of digits (I think that it probably should be
> 0.3333333333333333148296) so that when the number is read back into
> awk, it is still the same in the machine representation. I checked the
> manual, but I don't see a way to do so. Does anybody know how to do
> it? Thanks!

This should set you up:

  BEGIN { printf "%.20g\n", 1/3 }

Explanation of the 20 part:

  . Numbers in Gawk are represented as the 'double' data type, which
    has at most 17 significant digits.

  . You need 3 more places, one for the decimal, the other for the
    sign, and one more for the leading zero, if needed.  This gives
    20.

  . The %g format displays the shorter of %f and %e, and always
    displays the number of significant digits as instructed, so use
    that.