Re: PERL Countdown Timer

(A quick aside: The language is Perl, not PERL.)

use strict;
use warnings;

my $countdown = 1*60*60; # in secs.

$| = 1;

my $beg_time = time;
my $end_time = $beg_time + $countdown;

for (;;) {
   my $time = time;
   last if ($time >= $end_time);
   
   printf("\r%02d:%02d:%02d",
      ($end_time - $time) / (60*60),
      ($end_time - $time) / (   60) % 60,
      ($end_time - $time)           % 60,
   );

   sleep(1);
}

print("\rKABOOM!!!!\n");
[download]

Below is an alternative, but it will drift. That means that if you count down for 12 hours, it may take 12 hours and 5 minutes, or even much more than that, depending on CPU utilisation of other processes and more. I'm providing it as an example of what you should NOT do.

Bad code:

use strict;
use warnings;

my $time_left = 1*60*60; # in secs.

while ($countdown--) {
   printf("\r%02d:%02d:%02d",
      $time_left / (60*60),
      $time_left / (   60) % 60,
      $time_left           % 60,
   );

   sleep(1);
}

print("\rKABOOM!!!!\n");
[download]

Comment on Re: PERL Countdown Timer Select or Download Code

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Re^2: PERL Countdown Timer by zentara (Cardinal) on Nov 16, 2004 at 18:13 UTC
A minor nit-pick, you need a `$\|++;` [download] in your code, or the timer will not update the display properly. I'm not really a human, but I play one on earth. flash japh	[reply] [d/l]
Re^3: PERL Countdown Timer by ikegami (Patriarch) on Nov 16, 2004 at 18:33 UTC
oops, right, you need that on non-Windows systems. I tested my code in Windows, which line-flushes on \r and \n (as opposed to just on \n).	[reply]
Re^2: PERL Countdown Timer by Anonymous Monk on Feb 13, 2013 at 17:53 UTC
I put it in a simple sub. Easy to adjust if you want to include additional parameters such as a pre or post message. `countdown(10); sub countdown($) { #countdown(seconds); my ($duration) = @_; my $end_time = time + $duration; my $time = time; while ($time < $end_time) { $time = time; printf("\r%02d:%02d:%02d", ($end_time - $time) / (6060), ($en +d_time - $time) / (60) % 60,($end_time - $time) % 60); #00:00:10 $\|++; sleep 1; } }` [download] `countdown(10, "before", "after"); sub countdown($$$) { #countdown(seconds, "premessage", "postmessage"); my ($duration, $premessage, $postmessage) = @_; my $end_time = time + $duration; my $time = time; while ($time < $end_time) { $time = time; printf("\r%s %02d:%02d:%02d %s", $premessage, ($end_time - $ti +me) / (6060), ($end_time - $time) / (60) % 60,($end_time - $time) % +60, $postmessage); #before 00:00:10 after $\|++; sleep 1; } }` [download]	[reply] [d/l] [select]