use strict;

my %data=();
scan (0,'File1.txt');
scan (1,'File2.txt');
compare('log.txt');

# input
sub scan {
  my ($ix, $infile) = @_;
  open IN, '<', $infile or die "Could not open $infile : $!";
  my $count=0;
  while (<IN>){
    chomp;
    my ($key,$line) = split "\t",$_,2;
	$data{$key}[$ix] = $line;
	++$count;
  }
  close IN;
  print "$count lines read from $infile\n";
}

# output
sub compare {
  my $logfile = shift;
  open LOG,'>',$logfile or die "Could not open $logfile : $!";
  my $count = 0;
  
  # compare lines of data using key
  for my $key (sort keys %data){
    if ($data{$key}[0] ne $data{$key}[1]){
	  my @f1 = split "\t",$data{$key}[0];
	  my @f2 = split "\t",$data{$key}[1];
	  for my $c (1..@f1){
        if ($f1[$c-1] ne $f2[$c-1]){
		  print LOG "Row $key Column $c File 1 Value- $f1[$c-1] File 2 Value- $f2[$c-1]\n";
		  ++$count;
		}
      }	  
	}
  }
  close LOG;
  print "$count lines written to $logfile\n";
}