Look at the example we considered in class. The code is found on p. 149 of your text.
The local cub scout pack has their annual pop corn sale. They
sell large packages of microwave popcorn for $10 and a tin of caramel
corn for $5.50.
Construct the interface so that a customer could enter how many
packages of each he or she desired. There should be two Entry
items, correctly labeled. There should also be a “submit
order” button and when the customer “clicks” the
correct order total should be displayed at the bottom. Display a
message for the customer to click again before you close the window.