use strict;
use warnings;
my ($i, $j) = @ARGV;
my $acker = ackermann($i, $j);
print "A($i,$j) = $acker\n";
my $iter = 0;
sub ackermann{
	$iter ++;
	my $i = shift;
	my $j = shift;
	print "Iteration $iter: i = $i, j = $j \n";
	return if $iter >= 40;
	if($i == 1){
		undef $i;
		return 2**$j;
	}
	elsif($j==1){
		undef $j;
		return ackermann($i-1,2);
	}
	else{
		return ackermann($i-1, ackermann($i,$j-1));
	} 
}
##</code><code>##

$ perl  pseudo_acker.pl 3 4
Iteration 1: i = 3, j = 4
Iteration 2: i = 3, j = 3
Iteration 3: i = 3, j = 2
Iteration 4: i = 3, j = 1
Iteration 5: i = 2, j = 2
Iteration 6: i = 2, j = 1
Iteration 7: i = 1, j = 2
Iteration 8: i = 1, j = 4
Iteration 9: i = 2, j = 16
Iteration 10: i = 2, j = 15
Iteration 11: i = 2, j = 14
Iteration 12: i = 2, j = 13
Iteration 13: i = 2, j = 12
Iteration 14: i = 2, j = 11
Iteration 15: i = 2, j = 10
Iteration 16: i = 2, j = 9
Iteration 17: i = 2, j = 8
Iteration 18: i = 2, j = 7
Iteration 19: i = 2, j = 6
Iteration 20: i = 2, j = 5
Iteration 21: i = 2, j = 4
Iteration 22: i = 2, j = 3
Iteration 23: i = 2, j = 2
Iteration 24: i = 2, j = 1
Iteration 25: i = 1, j = 2
Iteration 26: i = 1, j = 4
Iteration 27: i = 1, j = 16
Iteration 28: i = 1, j = 65536
Iteration 29: i = 1, j = inf
Iteration 30: i = 1, j = inf
Iteration 31: i = 1, j = inf
Iteration 32: i = 1, j = inf
Iteration 33: i = 1, j = inf
Iteration 34: i = 1, j = inf
Iteration 35: i = 1, j = inf
Iteration 36: i = 1, j = inf
Iteration 37: i = 1, j = inf
Iteration 38: i = 1, j = inf
Iteration 39: i = 1, j = inf
Iteration 40: i = 1, j = inf

##</code><code>##

return 2**$j;

##</code><code>##

sub acker {
	my ($m, $n) = @_;
	return $n + 1 if $m ==0;
	return acker( $m-1, 1) if $n == 0;
	return acker ($m - 1, acker ($m, $n - 1));
}