Input and Output
Regardless of the type of application, a computer program almost always performs three basic functions: 1. Input some data. * From a file. * From the keyboard. 2. Process the data. * Formatting. * Calculating. * Searching. * Sorting. 3. Output the processed data. * To a file. * To the screen. * To a printer.
Input involves gathering data from somewhere (a user, a file, a database, etc.) and bringing it into your application program so that it can be used.
Process involves manipulating the data in a variety of different ways.
Output involves taking the results of the process and sending it somewhere (to a user, to a file, to a database, etc.).