Undefined subroutine &main::floor called

解决方法
http://stackoverflow.com/questions/37020135/perl-floor-function-giving-error-undefined-subroutine-mainfloor

sub floor {
    my ($n) = @_;
    my $int_n = int($n);
    $n < 0 && $int_n != $n ? $int_n - 1: $int_n;
}