Discount Calculator

The price after discount is displayed from a price and a discount rate.

1. An input of a price and a discount rate will display the price after discount.
2. If it clicks an "additional" button, it will be added to a list.
3. A click of a "list" button will display the price after discount in a list.
(Only the calculation result which clicked the "Add" button is displayed.)
4. A click of "delete" button will delete all lists.