HOW BAR CODES WORK
A supermarket computer system has in its memory the bar code for each item in the store. The computer also has in its memory the price of each item. If a store has a sale on canned fruit, for instance, the store manager does not have to change the prices on the cans. Instead, he changes the price in the computer memory. When a sale item is scanned, the computer reads the bar code. k enters the new price into the cash register. Bar codes also help stores count what they have sold. As items are scanned, the computer automatically counts them. At the end of each day, the store manager knows what the store has sold. For example, he knows that he still has enough canned fruit, but that he must order more coffee.