The "LOGIC" in Quizes PHP+MySQL - php

Question

I have a Database (MySQL) where is a table called: "dbtest" has the following fields,
id + v + o1 + o2 + o3 + o4 + g
to clarify that:
v: are the questions field
o1: the first answer
o2: the second
o3: third
o4: forth
g: is the right answer, where I put the number of the right answer for example, if I had a question with a correct answer "o3" the value of "g" should be "3"
(I did that myself thinking would be easier hopefully)
We yet did not reach the point I know, the thing is that I'm building a quiz program standing on the previous scheme, I made a page that calls the questions from the database and post them one below the other, the code was as the following:
<?php
include "config.inc";
$SQL = "SELECT * FROM test";
$query = mysql_query($SQL) or die();
echo "<form action=grade.php method=POST>";
while ($row = mysql_fetch_assoc($query)) {
echo "<p>$row[id]. ";
echo "$row[v]<br>";
echo "<input type=radio name=answer[$row[id]] value=$row[o1]>$row[o1]</input><br>";
echo "<input type=radio name=answer[$row[id]] value=$row[o2]>$row[o2]</input><br>";
echo "<input type=radio name=answer[$row[id]] value=$row[o3]>$row[o3]</input><br>";
echo "<input type=radio name=answer[$row[id]] value=$row[o4]>$row[o4]</input><br>";
}
echo "<input type=submit name=submit value=Check>";
echo "</form>";
?>
The problem is when I wanted to write the "grade.php" page I fell off an edge, I absolutely lost, I could do it if there was just one question in the database, so no need to enter a loop, but since the database is expected to receive tons of question I lost control.
I was trying something like,
<?php
include "config.inc";
$SQL = "SELECT * FROM test";
$query = mysql_query($SQL) or die();
$n = 0;
while ($row = mysql_fetch_assoc($query)) {
$n++;
$ques[$n] = $_POST['answer'];
if ($ques[$n] == $row[g]) {
echo "<font color=green>Correct</font>"; }
else {
echo "<font color=red>Incorrect<br></font>"; }
}
?>
But did not make it, all what I need is to process the questions and give right/wrong answers, for every right answer (+1) for every wrong one (-1) then I will post the sum mathematically.

Answer 1

In HTML your have to change radio button :
No need to add </input>,
For value you set answer number,
Add quotes for attributes
echo '<input type="radio" name="'.$answer[$row['id']].'" value="1" />'.$row['o1'].'<br>';
echo '<input type="radio" name="'.$answer[$row['id']].'" value="2" />'.$row['o2'].'<br>';
echo '<input type="radio" name="'.$answer[$row['id']].'" value="3" />'.$row['o3'].'<br>';
echo '<input type="radio" name="'.$answer[$row['id']].'" value="4" />'.$row['o4'].'<br>';
In PHP :
You create some variables to store good and bad answers,
You check if value of $row['g'] is equal to answer number
$query = mysql_query("SELECT * FROM test") or die();
$good = 0; // Number of good answers.
$bad = 0; // Number of bad answers.
while ($row = mysql_fetch_assoc($query))
{
if ( $_POST['answer'][$row['id']] == $row['g'] )
{
echo '<span style="color: green;">Correct</span>';
$good++;
}
else
{
echo '<span style="color: red;">Incorrect</span>';
$bad++;
}
}