use strict;
my @array = qw( wilma fred barney betty );
my $ctr = 0;
my $next_name;
foreach my $name ( @array ) {
    print "$name is the current element.\t";

    # Before using the next element, test for its existence.
    $next_name =
        exists $array[ $ctr + 1 ]
            ? $array[ $ctr + 1 ]
            : "unavailable"
                ;

    # Or you could break out immediately or perhaps have some
    # "end of array" code:
    # last if $next_name eq 'unavailable';
    # or:
    # if ( $next_name eq 'unavailable' ) {
    #      # do whatever you do when no more elements
    # }

    print "The next element is $next_name.\n";

} continue { 
    $ctr ++;
}

# Use of the '} continue {' line is more fancy than necessary;
# It's useful if you plan to break out of your loop with
# a 'next' command.