PHP订单提交总计算

Question

I made an order form using PHP that makes subtotals for each item ordered. How can I make a function/code to display the total for the order in the bottom of the page. I tried to read on PHP.net but couldn't figure it out.

Here is a sample of my code:

$bread = $_POST["bread"];
$cheese = $_POST["cheese"];
$eggs = $_POST["eggs"];

$priceBread = 5;
$priceCheese = 5;
$priceEggs = 3.6;

function subtotal($incomingQuantity, $incomingPrice){
  return $incomingQuantity * $incomingPrice;
}

<div id="breadSubtotal">$<?php echo subtotal($bread, $priceBread); ?>
<div id="cheeseSubtotal">$<?php echo subtotal($cheese, $priceCheese); ?></div>
<div id="eggsSubtotal">$<?php echo subtotal($eggs, $priceEggs); ?></div>

I want the total from the subtotals of all the items

</div>

Answer 1

something like this?

$total = 0;

function subtotal($incomingQuantity, $incomingPrice){
  global $total;
  $sub = $incomingQuantity * $incomingPrice;
  $total += $sub;
  return $sub;
}

then in the HTML

<div id="total">$<?php echo $total; ?></div>

also, dont forget to make safe your incoming $_POST vars with something like

$bread = htmlspecialchars($_POST["bread"]);