Perl rounding error again

Question

The example to show the problem:

• having a number 105;
• divide with 1000 (result 0.105)
• rouded to 2 decimal places should be: 0.11

Answer 1

I'd add use bignum to your original code example.

use 5.014;
use warnings;
use bignum;

my $i = 105;                # Parsed as Math::BigInt
my $r = $i / 1000;          # Overloaded division produces Math::BigFloat
say $r->ffround(-2, +inf);  # Avoid using printf and the resulting downgrade to common float.

This solves the error you made in your use Math::BigFloat example by parsing your numbers into objects imediately and not waiting for you to pass the results of a round off error into Math::BigFloat->new