Write a Java program to simulate an online store. The program should begin by

displaying a list of products and their prices. There should be a minimum of $4$ products

offered. The program should ask the user to choose a product and then ask the user to

enter the quantity they require of that product. The program should then allow the user

to keep choosing more products and quantities until they enter something to indicate

they want to end the program $($e$.$g$.$ a given number or $$q$$ or $$exit$).$ The program should

then tell the user the total amount for the products they have selected.