Barcode scanner is a very common tool in most of the shopping mall. When you bought something from the shop, the cashier will just scan your merchandise with the barcode scanner. It is very easy and convenient. In the olden days, when there is no barcode scanner, the cashier needs to key in the merchandise code one by one. It is time consuming and sometimes, cashier will make mistake by keying the wrong code. With the implementation of barcode system, human error can be reduced.