Computer Science Essentials Vocabulary

In MIT App Inventor, a control block that looks for inputs or events to know when to perform a specific action.

A function of an application or user interface

A technique or process that manages complexity in a program or computer system. It “hides” details or removes duplication, allowing the programmer to focus on high-level considerations and functions rather than the rules of a programming language.

An action or occurrence that happens during runtime that will trigger a response or behavior by the software. It can be user input, such as clicking a button, or external, such as a device receiving an SMS text message.

A function or artifact in an app that you can add in Design view of MIT App Inventor. Examples are: Canvas, Camera, Label, Slider, Sound, Horizontal arrangement, Button

The smallest unit of data storage that a program can use. It contains known or unknown information referred to as a “value.” Two types of variables are global and local.

To identify errors or bugs in computer hardware or programs and fix them.

A sequence of actions or instructions to follow in solving a problem or accomplishing a task. Also called subprogram, it is a group of statements that may be used at one or more points in a computer program. In MIT App Inventor, many commonly used ones are premade.

Image that can be coded to move within the canvas

A process of repeating a set of instructions a specified number of times or until a condition is met, such as in a repetition of a process or a newer version of development in computer science.

A processing decision branch using relational operators (= ≠ > <) that is defined to return a value (“true” or “false”). By using this expression to ask questions, the program can determine what to do next.

A joining together of separate items—without changing them—into one place. For example, doing this to two strings such as “Hello” and “world!” would return “Hello world!”

A set of steps to accomplish a task. It can be expressed in many kinds of notation, such as natural language, pseudocode, and flowcharts. They are essential to the way computers process data, because they contain the specific instructions for what a computer or program does.

Text or characters displayed by a program. In MIT App Inventor block mode, a text block lets you manage how text will be presented to the user of an app.

The values that a program provides to a function or subroutine. Sometimes coding professionals use the term “parameter” interchangeably. In this course, it is a better choice because Python does not use the term parameter.

A representation of a statement that is used to examine the relationship between two values and determine whether the statement is true or false (Boolean conditionals). Examples of these operators are AND, OR, and NOT.  

A series of conditionals that a computer moves through until it finds the one that is true

A programming statement that evaluates a true/false Boolean expression to determine the next steps in a program. These statements are often written as "if-then" or "if-then-else" statements. 

A symbol in code that tells a computer to perform a specific math operation, such as addition, subtraction, multiplication, or division.

 The = ≠ > < operators used to compare two items. They are also referred to as comparison operators.

Stored data that is only used within a small scope of a project and cannot be used by other parts of the program

A whole number that does not have a decimal or any digits after the decimal. 

A way to work out the logic without worrying too much about the specifics of the language you are programming in.

The language that people use in daily conversations with each other.

Stored data that may be used by any part of the program. A variable is simply a storage location for a value that is known or may be changing often based on inputs. By making a variable this it means all parts of the program can access it. Only using this variable in large programs can create problems because how the data is used in subroutines might be slightly different

A loop that changes the value of a count by a certain amount every time an event occurs.

reduced in number by one

A description of the parts of a program where a particular variable can be accessed and modified.

A sequential and prioritized list of what needs to be done to create the app the user wants. The list can be technical requirements or user centric in the form of user stories.

A control flow statement that allows a set of instructions to be executed repeatedly. This loop is usually used when the number of iterations is predefined “execute this loop so many times.” Otherwise, a programmer might use a different loop, which would execute the loop repeatedly as long as a certain condition is met.

A control flow statement that is a repeating if statement. The while loop will continue to execute indefinitely for as long as the condition being evaluated is true.

A sequence of instructions that continually repeats until a condition is met.

A structured collaborative process in which two people create code together, each with a specific role. The “driver” types at the keyboard and the “navigator” directs the code creation based on the requirements of the development. It is important to switch roles in the process often and maintain equity in the collaboration (avoid one person being dominant).