A program is a set of data or instructions that controls the behavior of a machine. Examples include:
Some programmable equipment and appliances only allow their users to select predefined options and/or set predefined parameters. The user is not required or allowed to write a computer program (textual, visual, or otherwise).
When a programmable computer, programmable calculator, or programmable logic controller executes a program, its processor follows the instructions or commands that the program contains. Each instruction produces effects that alter the state of the machine according to its predefined meaning.