Computer Program

A sequence of instructions that performs a specific task when executed by a computer.


A value in a computer program that constitutes text (as opposed to numbers of some other type of data).

Interactive Mode

A type of engagement between a human and a computer in which the computer prompts the humand for data and/or commands and may respond with output that the human can read and/or interpret.

Read-Evaluate-Print Loop

An interactive cycle in which the R-interpreter reads an expression from the console, evaluates it, and prints out the value to the console.

Data Structure

A particular way of organizing information in an computer program so that it can be used efficiently.


A character in a programing languages that is used to mark the beginning and/or end of a value.