Demonstrates machine epsilon in Perl

epsilon.pl

#!/usr/bin/perl
use warnings;
use strict;

my $val1;
if(($ARGV[0] // '') eq 'fixed') {
  require Math::FixedPoint;
  $val1 = Math::FixedPoint->new(2.1, 2); # fixed-point number
} else {
  $val1 = 2.1; # floating point number
}

while($val1 * 10 == $val2) {
  $val1 += 0.1;
  $val2 += 1;
}

printf "Epsilon exceeded at (\$val1 = %0.16f) * 10 != (\$val2 = %d)\n", $val1, $val2;

Example:

$ perl epsilon.pl
Epsilon exceeded at ($val1 = 2.3000000000000003) * 10 != ($val2 = 23)
$ perl epsilon.pl fixed
^C