Yet another C# problem

Sorry. Need help again with yet another C# problem. Please help. I've done all I could and just can't get it right.




I can't seem to get loop to work correctly. I also can't figure out how to store the quantities and display them at the end.

Here is the problem.
3. Console app: A store only sells 4 items: Milk (barcode “732”; $4.50 per gallon; 0% sales tax), laundry detergent (barcode “120”; $8 per container; 9.5% sales tax), newspapers (barcode “222”; $1.50 each; 4% state tax) and boxes of cigarettes (barcode “000”; $10 each; 120% sales tax). Develop a program for a point of sale (POS) machine that does the following:
a. Waits for cashier to type in “checkout” or “logout”; if the latter, exit the application; else for checkout go thru following steps:
b. “scans” each item – on one line, enter barcode, a space, and then quantity. For each item:
i. Check if barcode recognized and qty numeric and > 1. If either not met, print an error msg and go back to (b).
ii. Calculate subtotal and tax (applying correct tax for the item), and add to order total.
iii. Add item line to receipt string.
c. Repeat (b) until a blank line is entered, then calculate and print a receipt similar to the following in format (note column alignments):
Milk $ 5.00 x 4 $ 20.00
Laundry Det $ 8.00 x 1 $ 8.00
---------------------------------------------------
Subtotal $ 28.00
Tax $ 2.66
---------------------------------------------------
Total $ 30.66

d. Return to step (a)