Updating price information and displaying previous price for restaurant menu

[changwl8888]

I have a program with restaurant menu and 3 food items..
in the program i can choose the food and update the price for multiple times..
And at the same time, i have sales report reporting price of each units and total..

But the program allow to update price at any time, i need the program to show previous price and show recent price...How is it? What functions should i use?

the sales report should look like this..
Total Sales:
Muffin: 16 $32.00
Muffin: 2 $10.00
Muffin: 3 $30.00
Shake: 0 $0.00
Coffee: 0 $0.00
-----------------------
16 $32.00

for now i have already finished the coding..but i need to produce something can update price and previous price is keep...like example above...anyone ideas?

[pbrockway2]

One way would be to have a class representing a Price. That class could have an accessor method getPrice() returning a double value for use in arithmetic by the caller. But it could also offer getPreviousPric e() returning the value before the most recent change.