如何在结帐页面显示总价[OpenCart]

I would like to make some calculations at the checkout page. If for example the total price of all products is 80€, I want to show a message that says: "You can add more products on cart worth of 20€, so you can get a discount which activates when total cost is 100€".

To do this I have to get the total price as a variable and do this:

$tp = totalprice;

if ( $tp < 100 ) {
    $tp_less = 100 - $tp;
}

echo 'You can add more products on cart worth of ' . $tp_less . '€.';

The problem here is that I don't know how to get the total price as a variable.

<?php echo $cart_total = $this->cart->getTotal(); ?>

I placed the above at the file /checkout.tpl but I get an error so it's not working. Actually, whenever I use any code that has 'this' inside it I get error:

"Notice: Undefined property: Template\Basic::$cart"

All I had to do was:

At file checkout.php $data['total'] = $this->cart->getTotal();

At file checkout.tpl echo $total

$this->cart->getTotal() - Calculates cart total including taxes

$this->cart->getSubTotal() - This calculates products subtotal, I think you need to use this.

$this->cart->getSubTotal() - call this function in your controller and store value in a variable and pass it to your tpl file.

Regarding your error:

By default cart library is included in opencart, Make sure cart library is included, check registry file

Hope this helps.