How to get total during a foreach - php

Question

I am learning PHP, and trying to output the total of the "Price" column.
Here's what it looks like right now:
http://imgur.com/X00o4jS
Here's the code:
while($row = $result->fetch_array()){
$rows[] = $row;
}
foreach($rows as $row){
$food = $row["food"];
$price = $row["price"];
$id = $row['id'];
if(!empty($_POST[$id])){
$qtyPrice = $price * $_POST[$id];
$qty = $_POST[$id];
}
echo "<tr>
<td>$food</td>
<td>$qty</td>
<td>$$qtyPrice</td>
</tr>";
}

Answer 1

No need to do 2 loops. You are setting the array with the 1st while loop and then using a 2nd foreach loop just to read it and display the data.
It will be more efficient to use the while loop to generate your html table directly.
You can use $total += $qtyPrice (same as $total = $total + $qtyPrice).
Just remember to set it to 0 before the loop.
$total = 0;
while($row = $result->fetch_array()){
$food = $row["food"];
$price = $row["price"];
$id = $row['id'];
if(!empty($_POST[$id])){
$qtyPrice = $price * $_POST[$id];
$qty = $_POST[$id];
$total += $qtyPrice;
echo "<tr>
<td>$food</td>
<td>$qty</td>
<td>$$qtyPrice</td>
</tr>";
}
//display the total in its separate row
echo "<tr><td>Total:</td><td></td><td>$total</td></tr>";
Hope this helps!

Answer 2

set a variable before starting the loop, and adding the qtyPrice at it. Print that variable after exit the loop
$total = 0;
foreach($rows as $row){
$food = $row["food"];
$price = $row["price"];
$id = $row['id'];
if(!empty($_POST[$id])){
$qtyPrice = $price * $_POST[$id];
$total += $qtyPrice;
$qty = $_POST[$id];
}
echo "<tr>
<td>$food</td>
<td>$qty</td>
<td>$$qtyPrice</td>
</tr>";
}
echo $total;