#!/usr/bin/perl -w

print "Number of disks? ";
chomp( my $numdisks = <STDIN> );
print "Sleep? ";
chomp( my $sleep = <STDIN> );

$numdisks ||= 8;
$sleep    ||= 0.1;

my $board = [ [], [], [], [] ];
push @{$board->[1]}, $_ for reverse 1 .. $numdisks;
my %tower = map{ my $str =' 'x($numdisks-$_).'o'x$_;
                 $str = $str.($_?'+':'|').reverse($str); 
                 $_, " $str " } 0..$numdisks;

hanoi( $numdisks );

sub hanoi {   
    my $n   = shift;
    my $n1  = $n+1;
    my @D   = (1)x$n1;
    my @s   = 1..$n1+1;
    my $dir = 1 & $n;  
    for(;;) {
        my $i = $s[0];
        do{ show($n,0,0,1); last } if $i>$n;
        my $to =($D[$i]+($i&1?$dir:1-$dir))%3+1;
        show( $i, $D[$i], $to );
        $D[$i]   = $to;
        $s[0]    = 1;
        $s[$i-1] = $s[$i];
        $s[$i]   = $i+1;
    }
}

sub show {
    my ( $num, $from, $to, $show_final ) = @_;
    $^O =~ m/Win32/ ? system("cls") : system("clear");
    for my $i( reverse 0..$numdisks ) {
        print "\n", map{$tower{ $board->[$_]->[$i] || 0} }1..3;
    }
    return if $show_final;
    push @{$board->[$to]}, pop @{$board->[$from]};
    print "\n\nMove disk $num from $from to $to\n";
    select undef, undef, undef, $sleep;
}