An engineering program allows a user to key in two numbers and does a variety of different calculations with those numbers.

A point-of-sale program reads data keyed in by a sales representative and saves it on a hard disk.

An accounting program reads data from a flash drive, increases the sales values by 20%, and displays them on the screen before saving them back on the flash drive.

A sales program compares the sales values from two different products and displays the larger value on the screen.