#!/usr/bin/perl -w

use strict;

use vars qw($answer $correct $num @arr $errs);

$errs=0;

# Build questions
foreach my $i (1..10) {
	foreach my $j (1..10) {
		push (@arr,"$i * $j");
	}
}

# Loop block
{
	# Exit when all Q's are spliced away
	last unless defined $arr[0];

	# Get a random question (This will leave
	# 10 times 10 as the last question asked.
	# Use @arr instead of $#arr if you don't
	# like that behaviour. Please refer to
	# chipmunk's post for an explanation of
	# why.) 
	$num=int(rand $#arr);

	# Find the answer
	$correct=eval($arr[$num]);

	# Prompt for answer
	print "What is $arr[$num] ? \n";

	# Answering block
	{
		$answer=<STDIN>;
		chomp $answer;
		redo unless $answer=~m/^\d+$/;
	}

	# Right or wrong ?
	if ($answer == $correct) {
		print "Good, that's correct.\n";
		splice(@arr,$num,1);
	} else {
		print "No, that's not correct, $arr[$num] = $correct\n";
		$errs++;
	}

	# Tell how much it's left
	print "".($#arr+1)." questions left.\n\n";

	# And again...
	redo;
}

print "All done.\nYou made $errs misstakes.\n";