#!/usr/bin/perl

#solution to 2:
@array1 = (
	    ['John', 'Joe', 'Jim'],	
            [1, 2, 3],	
	    ['Jane', 'Joyce', 'Janine']
          );

print $array1[2][1], "\n";
print $array1[0][-2], "\n";
$array2_ref = [
            [1, 2, 3],	
	    ['John', 'Joe'],	
	    ['Jane']
          ];

print $array2_ref->[1][1], "\n";

#problem 3
open(IN, $ARGV[0]) or die "File $ARGV[0] does not exist!";

while (<IN>)
{
   chomp($_);
   @temp = split( / /, $_);
   push(@array3, [ @ temp ]);
}
close(IN);

#alternative using array references
#while (<IN>)
#{
#   chomp($_);
#   @temp = split( / /, $_);
   # note dereferencing @$array3_ref
#   push(@$array3_ref, [ @ temp ]);
#}
#print $array3_ref->[2][3], "\n";

#invert colors
#for $x ( 0 .. 8 )
#{
#   for $y ( 0 .. 8 )
#   {
#       if ($array3[$x][$y] == 1) { $array3[$x][$y] = 0; }
#       else {$array3[$x][$y] = 1; }
#   }
#}
#open (OUT, ">problem3_inverted.txt");
#foreach $rows (@array3)
#{
#   print OUT "@$rows\n";
#}

#close (OUT);

#solution to 3c-d
#invert colors

for $x (0 .. $#array3 )
{
   for $y ( 0 .. $#{$array3[$x]} )
   {
       if ($array3[$x][$y] == 1) { $array3[$x][$y] = 0; }
       else {
         $array3[$x][$y] = 1 if defined($array3[$x][$y]); }
   }
}

open (OUT, ">problem3c_inverted.txt");
foreach $rows (@array3)
{
   print OUT "@$rows\n";
}

close(OUT);

#solution to 4:
push(@array3, ['a', 'b', 'c', 'd']);
push(@{ $array3[2] }, (125, 125));