I'm sure that I'm making a very novice mistake. 
#!/usr/bin/perl

use strict;
use warnings;
use constant NEXT => 0;
use constant VAL => 1;

my ($list, $tail);
my($pred, $temp);
$list = $tail = undef;

# insertion. A linked queue.

foreach (1 .. 5) {
    my $node = [undef, $_ * $_];
    if(not defined $tail) {
        $list = $tail = $node;
    } else {
        $tail->[NEXT] = $node;
        $tail = $node;
    }
}
$temp = $list;

# print the values in the list.

while (defined $temp) {
    print $temp->[VAL], "\n";
    $temp = $temp->[NEXT];
}

# deletion

print "Enter element to be destroyed\n";
my $ele = <>;
chomp $ele;
$pred = $list;
$temp = $list->[NEXT];

while (defined $temp) {
    if($temp->[VAL] == $ele) {
        $pred->[NEXT] = $temp->[NEXT];
        print "$temp->[VAL] found!\n";
        $temp->[NEXT] = undef;
        last;
    } else {
        $temp = $temp->[NEXT];
    }
}

print "list after deleting $ele\n";

while (defined $list) {
    print $list->[VAL], "\n";
    $list = $list->[NEXT];
}

[download]
The insertion works perfectly. The output is as follows: 
1
4
9
16
25

[download]
now when I delete an element, I entered 4 and the output was the same minus 4. But when I delete 16, the output is: 
1
25

[download]
where am I going wrong?

In reply to Linked List by code-ninja

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