2024-2025 AP CS Principles Vocabulary Review

Iteration

A repetitive portion of an algorithm which repeats a specified number of times or until a given condition is met. Also called a "loop" or "looping".

Infinite Loop

Occurs when the loop goes on forever because the ending condition will never become true.

Simulation

A representation of a situation or problem with a similar but simpler model or a more easily manipulated model in order to determine experimental results.

For loop

A loop that has a predetermined beginning, end, and increment (step interval); should be used when the number of times the loop should execute is known before the program runs.

While loop

A loop that continues to repeat while a condition is true.

List

A generic term that refers to an ordered collection of elements. The AP CSP reference sheet uses this term instead of "array".

Array

The name typically used in programming to refer to a list of items managed and accessible by a given list name.

Element

An individual item in a list that is assigned a unique position referred to by an index.

Index

A number used to access the elements in a list or string based on its position in the list.

Append

Add an element to the end of a list.

Data Abstraction (List)

Helps manage complexity in a program because it simplifies the program code since the entire collection can be manipulated using the list name and an index.

Substring

Part of an existing string.

Function

A named group of programming instructions that may have parameters and return values. Also referred to as a "procedure".

Function Call

A command that executes the code within a function by using the function's given name with parentheses

Procedure

The generic term for function; refers to a named block of code without implying any particular programming language. The AP CSP reference sheet uses the term PROCEDURE instead of a …

Boolean Value

A data type that is either true or false.

Boolean Expression

A data type that evaluates to either true or false.

Comparison Operators

These, <, >, <=, >=, ==, !=, are used to indicate a Boolean expression.

Logical Operator

These, NOT ( ! ), AND ( && ), and OR ( || ), evaluate to a Boolean value.

Conditional Statement

Affects the sequential flow of control by executing different statements based on the value of a Boolean expression.

Modulus or MOD Operator

Is used to provide the remainder of a division problem as an integer value; for example, 22 MOD 7 is 1. In JavaScript, the percent symbol represents the MOD operator so 22 % 7 = 1.

Syntax Error

The code doesn't follow the rules of the programming language (usually generates a yellow triangle or red square in App Lab).

Logic Error

The code follows the rules of the programming language but doesn't function the way it's intended to.

Run-time Error

A mistake in the program that shows up when running the program.

Expression

A combination of operators and values that evaluates to a single value.

Assignment Operator

Allows a program to change the value represented by a variable; in JavaScript, it's the equal symbol (=); in pseudocode it's the left pointing arrow (←).

Variable

A named reference to a value that can be used repeatedly throughout a program.

String

An ordered sequence of characters; in JavaScript, strings are always within double quotes.

Concatenation

The joining together of two or more strings end-to-end to make a new string; in JavaScript, the plus symbol is used to concatenate two strings together.

Global Variable

A variable that can be used and updated by any part of the code; usually defined at the top of the program.

Local Variable

A variable that can only be seen, used, and updated within the function or onEvent where it is defined.

Pseudocode

A notation resembling a simplified programming language, used in program design.

Input

Data that are sent to a computer for processing by a program. Can come in a variety of forms, such as tactile interaction, audio, visuals, or text.

Output

Any data that are sent from a program to a device. Can come in a variety of forms, such as tactile interaction, audio, visuals, or text.

Program Statement

A command or instruction. Sometimes also referred to as a code statement.

Program

A collection of program statements. Programs run (or "execute") one command at a time.

Sequential Programming

Program statements that are run in order, from top to bottom.

Event-Driven Programming

Program statements that run when triggered by an event, like a mouse click or a key press (in code.org, these are implemented as "onEvents").

Documentation

A written description of how a command or piece of code works or was developed.

Comment

Form of program documentation written into the program to be read by people and which do not affect how a program runs.

Pair Programming

A collaborative programming style in which two programmers switch between the roles of writing code and tracking or planning high level progress.

Debugging

Finding and fixing problems in an algorithm or program.

Development Process

The steps or phases used to create a piece of software. Typical phases include investigating, designing, prototyping, and testing.

Event

Associated with an action and supplies input data to a program. Can be generated when a key is pressed, a mouse is clicked, a program is started, or by any other defined action that affects the flow of execution.

Incremental Development Process

A design approach that breaks the problem into smaller pieces and makes sure each piece works before adding it to the whole.

Iterative Development Process

A design approach requires refinement and revision based on feedback, testing, or reflection throughout the process. This may require revisiting earlier phases of the process.

Program Requirement

A description of how a program or software feature should work. For example: "When the right-arrow button is selected on screen 1, the program should advance to screen 2".

Program Specification

A complete description of how the program is specified to work. Sometimes referred to as the "Program Spec" or "Design Spec", it's usually a document that contains all of the requirements for the program.

Syntax Error

A mistake in the program where the rules of the programming language are not followed.

Software

A program or a collection of programs.

Investigate and Reflect Phase

First step in the development process to decide on how the app will work and what it will do; get user input to help guide the program and UI design.

Design Phase

The second step in the development process where a program or design specification is created that indicates how the program will work and/or how users will interact with it

Coding Phase

The third step in the development process where the programmer writes the code and tests it as it's being developed (according to the design spec).

Testing Phase

The final step in the development process where the final version of the program is tested to make sure it works as expected; usually revisions are made so bugs are not shipped to the customer.

User Interface (UI)

The inputs and outputs that allow a user to interact with a piece of software. User interfaces can include a variety of forms such as buttons, menus, images, text, and graphics.

HTML

creates the content of a website

CSS

changes the appearance of a website

Javascript

makes the website interactive

Syntax

rules we have to follow when using a programming language

Integer

a number that doesn't have a decimal part

Float

a number that includes a decimal part

String

represents text inside of single or double quotes

Concatenation

adding separate strings together to form one string

Character

a single letter, number, or symbol in a piece of text

HTML tag

used to group element code together

Parameter

A variable in a function definition. Used as a placeholder for values that will be passed through the function.

Argument

The value passed to the parameter.

Return

Used to return the flow of control to the point where the procedure (or function) was called and to return the value produced by the procedure (if applicable).

Modulus Operator (or "MOD")

The remainder as an integer value that results from dividing two numbers. For example, the MOD operator in JavaScript is the percent symbol "%" so 8 % 3 = 2.

Procedural Abstraction

A process that allows a procedure to be used only knowing what it does, not how it does it. Procedural abstraction allows a solution to a large problem to be based on the solution of smaller subproblems. This is accomplished by creating procedures to solve each of the subproblems.