Marking function for an online exam not working.

[morocco-iceberg]

I'm only new to this and am getting a bit stuck.

 

Basically function sent() outputs a set of questions within a form, the user answers the questions and function mark() is supposed to check whether the user got the answers correct.

 

The output of sent() is a group of dropdown boxes that thes user has to construct a sentence from. The dropboxes contain preset words.

 

My attempt at mark() is below, with the relevant code from sent() below that.

 

The specific error that I am receiving says "Notice: Undefined variable:" and then lists all of the letters.

 

How can I fix it/make it better/do it another way?

 

function mark($table){
$counter = 0;
while($counter<2){
	$id = $_POST[$table."_q".$counter];
	$sql = mysql_query("SELECT * FROM $table WHERE id = '{$id}'") or die($error);
	$letters = array("a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t");
	foreach($letters as $number => $letter){
		${'a'.$letter} = $_POST[$table."_a".$number];
		while($row = mysql_fetch_array($sql)){
			${$letter} = $row[$letter];
		}
		${'c'.$letter} = strcmp(${'a'.$letter}, ${$letter});
	}
	if ($ca == 0 && $cb == 0 && $cc == 0 && $cd == 0 && $ce == 0 && $cf == 0 && $cg == 0 && $ch == 0 && $ci == 0 && $cj == 0 && $ck == 0 && $cl == 0 && $cm == 0 && $cn == 0 && $co == 0 && $cp == 0 && $cq == 0 && $cr == 0 && $cs == 0 && $ct == 0){
		global $score;
		$score++;
	}else{
		global $score;
		$score = $score;
	}
$counter++;
}
}

 

function sent($table){
$sql = mysql_query("SELECT * FROM $table ORDER BY RAND()") or die($error);
$counter = 0;
while($row = mysql_fetch_array($sql)){
	$id[$counter] = $row["id"];
	$a[$counter] = $row["a"];
	$b[$counter] = $row["b"];
	$c[$counter] = $row["c"];
	$d[$counter] = $row["d"];
	$e[$counter] = $row["e"];
	$f[$counter] = $row["f"];
	$g[$counter] = $row["g"];
	$h[$counter] = $row["h"];
	$i[$counter] = $row["i"];
	$j[$counter] = $row["j"];
	$k[$counter] = $row["k"];
	$l[$counter] = $row["l"];
	$m[$counter] = $row["m"];
	$n[$counter] = $row["n"];
	$o[$counter] = $row["o"];
	$p[$counter] = $row["p"];
	$q[$counter] = $row["q"];
	$r[$counter] = $row["r"];
	$s[$counter] = $row["s"];
	$t[$counter] = $row["t"];
	$counter++;
}
$counter = 0;
while($counter<2){
	echo "<input type=\"hidden\" name=\"".$table."_q".$counter."\" value=\"".$id[$counter]."\">";
	${$table.'_a'.$counter} = array("$a[$counter]", "$b[$counter]", "$c[$counter]", "$d[$counter]", "$e[$counter]", "$f[$counter]", "$g[$counter]", "$h[$counter]", "$i[$counter]", "$j[$counter]", "$k[$counter]", "$l[$counter]", "$m[$counter]", "$n[$counter]", "$o[$counter]", "$p[$counter]", "$q[$counter]", "$r[$counter]", "$s[$counter]", "$t[$counter]");	
	${$table.'_c'.$counter} = ${$table.'_a'.$counter};
	shuffle(${$table.'_a'.$counter});
	$number = 0;
	echo "<table border=\"1\" bordercolor=\"#000000\" rules=\"none\" frame=\"box\" cellpadding=\"5\"><tr>";
	while($number<20){
		if(!${$table.'_a'.$counter}[$number]){
			echo "";
		}else{
			echo "<td>".${$table.'_a'.$counter}[$number]."</td>";
		}
		$number++;
	}
	echo "</tr></table><br/><table><tr>";		
	foreach(${$table.'_c'.$counter} as $column){
		if(empty($column)){
			break;
		}else{
			echo "<td><select name=\"".$table."_a".$counter."\"><option value=\"0\"></option>";
			$number = 0;
			while($number<20){
				if(!${$table.'_a'.$counter}[$number]){
					echo "";
				}else{
					echo "<option value=\"".${$table.'_a'.$counter}[$number]."_".$number."\">".${$table.'_a'.$counter}[$number]."</option>";
				}
				$number++;
			}
			echo "</select></td>";
		}
	}
echo "</tr></table><br/>";
$counter++;
}
}

[kenrbnsn]

Please tell use the exact error and which line it's referring to.

 

Ken

[morocco-iceberg]

Notice: Undefined variable: b on line 48 (minus the 36 lines not included means line 12 in the code I've provided).

 

Notice: Undefined index: sente_a2 on line 44 (line 10)

 

Notice: Undefined variable: c on line 48

 

Notice: Undefined index: sente_a3 on line 44

 

And it just goes on and on like that for each letter and number.