use strict; 
use warnings; 
 
my @array = (0..99); 
#my @rev_array = undef; 
 
my $counter = 0; 
 
 
foreach $counter(@array) 
{ 
	 
	$_ = $counter; #assign counter’s value to whichever array element $_ is currently pointing to 
	print 'the first $_ is: '.$_."\n"; 
	$counter++; #increment the counter 
	print 'the first $counter is: '.$counter."\n"; 
} 
 
#reset the counter 
$counter= 0; 
 
foreach $counter (@array) 
{ 
	print 'second $counter is: '.$counter."\n"; 
	print 'second $_ is: '.$_."\n"; 
	#if curr. array element is even then	 
	if ($_ %2==0)  
	{ 
		# remove it from the array referenced by $ array_ref 
		print 'inside the IF!\n'; 
		$_ = undef; 
	} 
	 
	$counter++; 
}

use strict;  
use warnings;  
use Data::Dumper;   
  
my @array   = ( 0 .. 99 );   
  
my $counter = 'This is never use';   
  
foreach $counter (@array) {  
#    $_ = $counter;   
  
#    print 'the first $_ is: ' . $_ . "\n";  
    $counter++;  
#    print 'the first $counter is: ' . $counter . "\n";  
}   
  
print Dumper( \@array, $counter );