#!/usr/bin/perl
use strict;
use warnings;
my @arr;
foreach(1..4)
{
push @arr,[0,0,0,0];
}
my ($i,$j);
for($i=0;$i<5;$i++)
{
for($j=0;$j<5;$j++)
{
print "$arr[$i][$j]\n";
}
}
#push @arr,[(0) x 4]foreach 1..4
my $change=3;my $b=4;
$change=$b==0 ? 'first':'end';print "\$change=$change,\$b=$b\n";
#$change=end,$b=4
my $n = '';$n = $n-2;print "$n\n";
#-2
my $m = 0;$n = $m == 0? 'null == 0':'null != 0';print "$n\n";