#! /usr/bin/perl

use strict ;
use warnings ;

my @complaints = (
                   {
                     'complaint_id' => 'a123',
                     'x'            => '45.2',
                     'y'            => '39.7'
                   },
                   {
                     'complaint_id' => 'b456',
                     'x'            => '79.3',
                     'y'            => '42.0'
                   },
                   {
                     'complaint_id' => 'c789',
                     'x'            => '11.9',
                     'y'            => '29.8'
                   },
                   {
                     'complaint_id' => 'd863',
                     'x'            => '95.3',
                     'y'            => '17.2'
                   },
                   {
                     'complaint_id' => 'e635',
                     'x'            => '65.5',
                     'y'            => '33.3'
                   },
                 ) ;

my ( $curr_x, $curr_y ) = ( 36.2, 47.3 ) ;

my @sorted_by_proximity = map { $_->[1]->{'dist'} = $_->[0]; $_->[1] }
                          sort { $a->[0] <=> $b->[0] }
                          map { [ distance( $curr_x, $curr_y,
                                            $_->{'x'}, $_->{'y'}
                                          ), $_
                                ]
                              } @complaints ;

foreach ( @sorted_by_proximity )
{
    print $_->{'complaint_id'} . " is " . $_->{'dist'} . " away.\n" ;
}

sub distance
{
    my ($x1, $y1, $x2, $y2 ) = @_ ;
    return sqrt( abs( $x2 - $x1 )**2 + abs( $y2 - $y1 )**2 ) ;
}