#!/usr/local/perl -w
use strict;
use warnings;
my @file = ('0.13','0.14','0.14');
my $diff = 0;
my @diffVal;

for (my $i=1 ; $i< scalar(@file) ; $i++){
  if ($diff < abs($file[$i-1]-$file[$i])){
    $diff = abs($file[$i-1]-$file[$i]);
    $diffVal[0] = $file[$i-1];
    $diffVal[1] = $file[$i];
  }
}

print "Difference between $diffVal[0] and $diffVal[1] is $diff\n" if (defined($diffVal[1]));