#!/usr/bin/perl
use strict;
use warnings;
use diagnostics;

#my $source = "./CONTCAR";
#my $destination = "./OUTPUT";
#
#open(IN, '<', $source) or die "Couldn't open $source: $!\n";
#open(OUT, '>', $destination) or die "Couldn't write to $destination: $!\n";

my @data = map [ split ], grep /\S/, <DATA>;

foreach (@data) { print "@$_\n"; }

for my $i (0 .. $#data-1) {
    for my $j ($i+1 .. $#data) {

#        next if $i == $j;

    my @coords_i = @{$data[$i]}[0,1,2];
    my @coords_j = @{$data[$j]}[0,1,2];

#        printf OUT "%s to %s Distance=%.5f\n",
    printf "(%s,%s) to (%s,%s) Distance=%.5f\n",
        $data[$i][0], $data[$j][0],
        $data[$i][2], $data[$j][2],
        distance(\@coords_i, \@coords_j);
    }
}

sub distance {
    my ($aa, $bb) = @_;
    my ($x, $y, $z) = map { $aa->[$_] - $bb->[$_] } 0 .. $#$aa;
    return sqrt($x**2 + $y**2 + $z**2);
}

#    close IN;
#    close OUT;

#    print "Done.\n";

exit;

__DATA__
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5