Perl sorts

I'm trying to do a bubble sort, selection sort, merge sort(not implemented yet) in perl but this randomly crashes no clue why any ideas...?


#!/bin/perl


&main();

sub main
{
    my @array = (1,7,4,9,4,7,2,3,0,8);

    print "Selection Sort\n\n";

    &selectionSort(\@array,);
    print "@array\n\n";

    print "Bubble sorting\n\n"; #crashes here sort of clears the terminal screen and prints 8,9

    my @secondarray =(7,8,9,3.2.10.12);
    bubble_sort(@secondarray);

    print "@secondarray\n\n";

    sleep(10);
} # main

sub selectionSort
{
    my $aref = shift(@_);

    for (my $x=0; $x<@$aref-1; $x++)
    {
        my $smallestIndex = $x;
        for (my $y=$x+1; $y<@$aref; $y++)
        {
         if ( $aref->[$y] < $aref->[$smallestIndex] )
         {
             $smallestIndex = $y;
         }
        } # for $y
        &swap( \$aref->[$x], \$aref->[$smallestIndex] );
    } # for $x
} # selectionSort

sub swap

{
    my ($x, $y) = @_;
    my $tmp = $$x;
    $$x = $$y;
    $$y = $tmp;
} # swap


sub bubble_sort {
    for my $i (0 .. $#_){
        for my $j ($i + 1 .. $#_){
            $_[$j] < $_[$i] and @_[$i, $j] = @_[$j, $i];
        }
    }
}

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