1. Current_results (File1.txt):
Distance   Fuel_Consumption
60	    2.0
80	    2.2
100	    3.0
200	    5.5
<EOF>

2. Baseline1 (File2.txt):
Distance   Fuel_Consumption
60	    1.0
80	    1.5
100	    2.3
200	    4.2
<EOF>

3. Output (Report.txt)

Distance  Fuel_Consumption_Curr	Fuel_Consumption_Baseline1
60	   2.0			1.0
80	   2.2			1.5
100	   3.0			2.3
200	   5.5			4.2
<EOF>


##</code><code>##

#!/usr/bin/perl -w

use strict;
use Data::Dumper qw(Dumper); 


my @list_of_files =  qw(file1.txt file2.txt);
my %data;
my $file_num = 0;
my $Distance;


foreach my $file_name (@list_of_files) {
    $file_num++;
    my $file = 'File'.$file_num;
    my $flag = 0;

    open FH, $file_name or die "Cannot open $file_name. $!";
    while(<FH>){
        chomp;
        if($_ =~ /\s*(\d+)\s*(\d+\.\d+)/){
		    $Distance=$1;
			 $data{$Distance}{$file}{'Fuel_Consumption'}=$2;
            next;
        }
       }
    close FH;
}

  print Dumper(\%data); 

  my ($tmpDist,$tmpFile,$tempValue);
  print "Merged output\n";
  
 foreach $tmpDist (sort{ $a <=> $b } keys( %data ) ) 
 {
    print "$tmpDist";
    foreach $tmpFile (sort{ lc($a) cmp lc($b) } keys( %{$data{$tmpDist}} ) )
     {
	  $tempValue=$data{$tmpDist}{$tmpFile}{'Fuel_Consumption'};
       print "\t $tempValue";
	 }
    print "\n";
 }

##</code><code>##

60       2.0     1.0
80       2.2     1.5
100      3.0     2.3
200      5.5     4.2