What Every Computer Scientist Should Know About Floating-Point Arithmetic

In short: repeated addition of ~0.1 is not the same as n instances of exactly 0.1.

Instead, do something like this:

use warnings;
use strict;
my $delta = 0.1;
my $v = 0;
my $i = 0;
while( $v < 9 ) {
  $v = $i * $delta;
  print $v, $/;
  ++$i;
}
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