PHP The value captured from the radio button is "On" - php

Question

I'm trying to capture question ids and their answers. The problem
is that the value is "ON" when I print the array, it has the
question number correctly in the first cell but then the value in the
second cell is "ON". Here is my code:
function get_questions($quiz_id)
{
include'connection.php';
$stmt = $conn->prepare("select id,question,option1,option2,option3,option4,answer from questions where quiz_id=?");
$stmt->bind_param("i",$quiz_id);
$stmt->execute();
$stmt->store_result();
$stmt->bind_result($qid,$question,$option1,$option2,$option3,$option4,$answer);
$num_of_rows = $stmt->num_rows;
while($stmt->fetch()) {
echo $question;
echo "<br/>";
?>
<form method="POST"action="">
<input type="radio" name="radio[<?php echo $qid; ?>]" ]value="x"><?php echo $option1;?><br/>
<input type="radio" name="radio[<?php echo $qid; ?>]" ]value="y"><?php echo $option2;?><br/>
<input type="radio" name="radio[<?php echo $qid; ?>]" ]value="z"><?php echo $option3;?><br/>
<input type="radio" name="radio[<?php echo $qid; ?>]" ]value="f"><?php echo $option4;?><br/>
<!--<input type="radio" name="radio[<?php echo $qid; ?>]" ]value="<?php echo $option2;?>"><?php echo $option2;?><br/>
<input type="radio" name="radio[<?php echo $qid; ?>]" ]value="<?php echo $option3;?>"><?php echo $option3;?><br/>
<input type="radio" name="radio[<?php echo $qid; ?>]" ]value="<?php echo $option4;?>"><?php echo $option4;?><br/>
-->
<?php
}
?>
<input type="submit" name="submit" value="submit" >
</form>
<?php
if(isset($_POST['submit'])) {
$answers=$_POST['radio'];
print_r($answers);
// Iterate through each answer
}
}

Answer 1

Your problem is a simple syntax error:
]value="x">
This square bracket is changing the name of the attribute from value to ]value, so there is no value to be captured upon submission.
Also, make sure to move the opening form tag outside of your loop:
while($stmt->fetch()) {
...
<form method="POST"action=""> // <- this here opens a new tag with each iteration
because you close the tag outside the loop, meaning you're not creating valid html.
And while we're here, I'd suggest the alternative syntax when you have mixed php and html code:
<form method="POST" action="">
<?php while ($stmt->fetch()): ?>
<input type="radio"...
...
<?php endwhile ?>
<input type="submit" name="submit" value="submit" >
</form>
It makes it more readable and easier to follow than having to match curly braces.