Select Code to Download

Select or download this
```
sub count_up {
{
...
    .
}
}
```

$cnt=0; $progress=0
$cnt=0; $progress=20
$cnt=0; $progress=40
$cnt=0; $progress=60

Select or download this

my $r = \$progress;
print("address of \$progress=$r\n");

Select or download this

$cnt=0; $progress=0
address of $progress=SCALAR(0x19fc970)
...
address of $progress=SCALAR(0x1cfdb0c)
$cnt=0; $progress=60
address of $progress=SCALAR(0x1d13fc4)

Select or download this

    $pb->configure(
        -from => 0,
...
        -variable => \$progress,  ## store the reference.
    );
$progress = 0;

Select or download this

$cnt=0; $progress=0
$cnt=0; $progress=0
$cnt=0; $progress=0
$cnt=0; $progress=0

Select or download this

sub variable {
    my $c = shift;
...
    }
    $oldval;
}

Select or download this

use strict;
use warnings;
...
        $mw->update;
    }
}