#!/usr/bin/perl 
#######################################################
### Written by Jeff Borders 
### http://www.jeffborders.com/scripts/korean.pl
### revised on 01/14/05 @ 07:21:00
###
### Perl program to take input file consisting
### of answer = question text and return a
### question and 4 possible answers.  Incorrect
### answers are immediately shown with correct answer.
### Totals and score shown upon exit.  Currently 
### setup for input file of korean taekwondo 
### terminology.
###
### In future, I will change the program to
### accept an argument for file name so the program can
### be used for any type of testing.  
### I'm thinking about making this web-based or maybe
### adding a gui and/or ms windows compatibility.
###
### This is offered with no guarantee that
### it will work on your system.  In fact, if it
### causes your PC to catch fire and burn you house
### down, you're on your own.
### Seriously though, if you have perl installed on your
### PC, it should work.

use warnings;
use strict;

my $number_of_questions=0;
my $random_question=0;
my $random_order=0;
my $response=0;
my $total=1;
my $incorrect=0;
my @answer;
my @question;
my $answer=0;
my $question=0;
my @answered=0;

die "USAGE: korean.pl <file>\n" unless @ARGV == 1;

open (DICT, $ARGV[0]) || die "Cannot open '$ARGV[0]' $!";
while (<DICT>) { 
	chomp;
	$number_of_questions++;
	($answer, $question) = split /\s*=\s*/;
	$answer[$number_of_questions] = $answer;
	$question[$number_of_questions] = $question;
	}
close DICT;

#open ERRFILE, '>', 'errfile.txt' or die "Cannot open 'errfile.txt' $!";

# Something I read in a book to make the rand function a little more random.
srand((time() ^ (time() % $])) ^ exp(length($0))**$$);


# Main Loop #
do {
	$total++;
	if ($total <= $number_of_questions) {
	&pick_question();
	&pick_order();
	&print_question();
	&get_response();
	print "\nQuestion number $total of $number_of_questions\n";
	}
} until ($response eq 'q' || $total > $number_of_questions);
&print_result();

#close(ERRFILE) || die "Couldn't close file properly";
#That's all folks.

### Subroutines ###
sub pick_question
	{ 
	### Pick unused question ###
	do {
	$random_question = 1 + int(rand($number_of_questions));
	} while ( grep (/$random_question/, @answered) );
	push @answered, $random_question;
	return $random_question;
	}

sub pick_order
	{ 
	$random_order = 1 + int(rand(4));	#returns an integer from (0..3) + 1. 
	return $random_order;
	}

sub print_question 
	{
	print "\n\nQuestion $total:  ";
	print "$question[$random_question]\n\n";
	my @temp_answers = 0;
	my $temp_answer = 0;
	push @temp_answers, $random_question;
	for my $i (1..4) {
	if ($i == $random_order) {
		print "$i. $answer[$random_question]\n";	#print correct value from array.
	  } else {
		### Make sure that bogus answer does not equal answer or other 2 bogus answers ###
		do {
		$temp_answer =  1 + int(rand($number_of_questions));
		} while ( grep (/$temp_answer/, @temp_answers) );
		push @temp_answers, $temp_answer;
		print "$i. $answer[$temp_answer]\n";	#print incorrect value from array.
	}
	#if ($i == 4 ) { print "@temp_answers\n"; }
    }

sub get_response
	{
	print "\npress q to quit\n";
	print "Enter your answer:  ";
	chomp($response=<STDIN>);
	if ($response eq 'q') 
	 { 
	  print "\n"; 
	  $total--;
	 } 
	elsif ($response != $random_order) 
	 { 
	  print "-----> $question[$random_question] is $answer[$random_question] <-----\n"; 
	  $incorrect++; 
	 }	#print correct value from array.
	return $incorrect;
	}

sub print_result
{
  if ($total == 0) { 
	print "No questions answered.\n";
	}
  else
	{
	my $percent=eval (($total-$incorrect)/$total)*100;
  	printf "Out of %2d questions, you missed %2d for a grade of %3d%%\n", $total, $incorrect, $percent;
	print "Total number of questions is $number_of_questions\n";
	#print "Order of Random Questions: @answered\n";
	}
  }
}