You were shopping, and now you have some products in your cart. You need to know whether you have enough money for the purchase. So you need to calculate a total size of the upcoming payment.
Each product is represented as an instance of the Product class. Each product has two fields: int amount
and int price. You should implement the Task.calculatePayment() method which takes the Cart cart argument.
The cart has the Product[] products field with an array of your products. The method should calculate a total price of
all your products and return it. The price of each product is its amount multiplied by its price.