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#!/usr/bin/perl
use Modern::Perl;
# Write a script that allows you to capture/display historical data.
my $h = Historical->new();
sleep 1;
$h->set(1);
$h->get_history();
sleep 1;
$h->set(1);
sleep 1;
$h->set(11);
sleep 1;
$h->set(111);
sleep 1;
$h->set(11);
sleep 1;
$h->set(1);
$h->get_history();
exit;
package Historical;
sub new {
my $class = shift;
my $now = time;
my $self = {
x => 0,
x_history => {$now => 0},
};
return bless $self, $class;
}
sub set {
my $self = shift;
my $next = shift;
if ($self->{x} != $next) {
$self->{x} = $next;
my $now = time;
$self->{x_history}{$now} = $next;
}
}
sub get_history {
my $self = shift;
say "History of x is:";
foreach (sort (keys %{ $self->{x_history} })) {
say "$_ => ", $self->{x_history}{$_};
}
}
__END__
./ch-2.pl
History of x is:
1569256589 => 0
1569256590 => 1
History of x is:
1569256589 => 0
1569256590 => 1
1569256592 => 11
1569256593 => 111
1569256594 => 11
1569256595 => 1
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