Can't delete without getting "Undefined Offset" error - php

Question

I'm doing a very simple project for my assignment and it's about shopping cart. I've created a cart page by using SESSION with array and index to keep track user's order. The problem is whenever I'm deleting a meal from my cart list, there'll be an error which is "Notice: Undefined offset: 1", "Notice: Undefined offset: 2", etc. I'm attaching my codes here:
This is my cart page. The error said it has something to do on the line that I have commented:
<form method="POST" action="save_cart.php">
<table class="table">
<tbody>
<thead>
<th></th>
<th>Name</th>
<th>Price</th>
<th>Quantity</th>
<th>Subtotal</th>
</thead>
<?php
//initialize total
$total = 0;
if(!empty($_SESSION['cart'])){
//create array of initail qty which is 1
$index = 0;
if(!isset($_SESSION['qty_array'])){
$_SESSION['qty_array'] = array_fill(0, count($_SESSION['cart']), 1);
}
$sql = "SELECT * FROM meal WHERE meal_id IN (".implode(',',$_SESSION['cart']).")";
$query = $conn->query($sql);
while($row = $query->fetch_assoc()){
?>
<tr>
<td class="removebtn" style="text-align: center;">
<a href="delete_item.php?id=<?php echo $row['meal_id']; ?>&index=<?php echo $index; ?>" >Remove</a>
</td>
<td><?php echo $row['meal_name']; ?></td>
<td>RM <?php echo number_format($row['meal_price'], 2); ?></td>
<input type="hidden" name="indexes[]" value="<?php echo $index; ?>">
<td class="qtyinput" ><input type="number" min="1" max="5" class="form-control" value="<?php echo $_SESSION['qty_array'][$index]; ?>" name="qty_<?php echo $index; ?>"></td>
//THE ERROR IS HERE
<td>RM <?php echo number_format($_SESSION['qty_array'][$index]*$row['meal_price'], 2); ?></td>
<?php $total += $_SESSION['qty_array'][$index]*$row['meal_price']; ?>
</tr>
<?php
$index ++;
}
}
else{
?>
<tr>
<td colspan="5" class="text-center" style="text-align: center;">No Meal in Cart</td>
</tr>
<?php
}
?>
<tr>
<td colspan="4" align="left"><b>Total</b></td>
<td><b>RM <?php echo number_format($total, 2); ?></b></td>
</tr>
</tr>
Here's my delete page:
session_start();
//remove the id from our cart array
$key = array_search($_GET['meal_id'], $_SESSION['cart']);
unset($_SESSION['cart'][$key]);
unset($_SESSION['qty_array'][$_GET['index']]);
//rearrange array after unset
$_SESSION['qty_array'] = array_values($_SESSION['qty_array']);
$_SESSION['message'] = "<script>alert('Meal is deleted from your cart');</script>";
header('location: cart.php');
I really need your help. Thanks in advance!

Answer 1

Its an index error because index doesn't exists in the array replace your html php code inside while loop with this one.
<tr>
<td class="removebtn" style="text-align: center;">
<a href="delete_item.php?id=<?php echo $row['meal_id']; ?>&index=<?php echo $index; ?>" >Remove</a>
</td>
<td><?php echo $row['meal_name']; ?></td>
<td>RM <?php echo number_format($row['meal_price'], 2); ?></td>
<input type="hidden" name="indexes[]" value="<?php echo $index; ?>">
<td class="qtyinput" ><input type="number" min="1" max="5" class="form-control" value="<?php echo (isset($_SESSION['qty_array'][$index]) ? $_SESSION['qty_array'][$index] : 0); ?>" name="qty_<?php echo $index; ?>"></td>
//THE ERROR IS HERE
<td>RM <?php
$qty = (isset($_SESSION['qty_array'][$index]) ? $_SESSION['qty_array'][$index] : 0);
echo number_format($qty *$row['meal_price'], 2); ?></td>
<?php $total += $qty*$row['meal_price']; ?>
</tr>