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Unit 1 · Creative Development Flashcards Cheat Sheet Essentials Visual Review MC Practice FRQ Practice

AP Computer Science Principles Unit 1 Essentials

The must-know terms and core concepts for Unit 1: Creative Development. Every vocabulary word and idea you need to master.

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Key Concept 1
Programs are created to serve a purpose — and collaboration makes them better
Every program has a function (what it does) and a purpose (why it exists and who it serves), and it interacts with the world through inputs and outputs. Programs are usually built by teams, and collaboration matters: diverse perspectives lead to more creative, more inclusive software and catch problems a single developer would miss. Effective collaboration depends on communication, consensus-building, and shared responsibility.
Function & Purpose Inputs & Outputs Collaboration
Key Concept 2
Good programs are built through an iterative, incremental process
Development is not a straight line. The AP CSP process cycles through investigating and reflecting, designing, prototyping, and testing, using feedback to refine the program each pass. Building incrementally — small, tested pieces — keeps the work manageable. Along the way, requirements define what the program must do, prototypes test ideas early, and documentation and comments keep the program understandable and maintainable.
Iterative Development Requirements & Prototypes Documentation
Key Concept 3
Errors are inevitable — identifying and correcting them is central to development
Real programs contain errors, and a key skill is classifying and fixing them. Logic errors let a program run but produce the wrong result; syntax errors break the language's rules and usually stop it from running; run-time errors occur during execution; and overflow errors happen when a value is too large for the available bits. Developers find and fix these through testing (varied inputs and test cases) and debugging (hand-tracing, display statements, isolating the problem).
Types of Errors Testing Debugging
Program
A collection of program statements that performs a specific task when run.
Programs
Program function
What a program does — its behavior.
Programs
Program purpose
Why a program was created and who it is intended to serve.
Programs
Input
Data a program receives while running, from a user, device, sensor, file, or another program.
Programs
Output
Data a program produces — visual, audible, tactile, or text.
Programs
Event
An action, such as a click or key press, that a program can respond to.
Programs
Event-driven program
A program whose actions run in response to events rather than in a fixed order.
Programs
Collaboration
Working with others, using diverse perspectives to build a better program.
Collaboration
Consensus
General agreement reached by a group when making decisions together.
Collaboration
Iterative development
A repeating cycle of investigating, designing, prototyping, and testing.
Development
Incremental development
Building and testing a program in small pieces.
Development
Requirements
A description of what a program is supposed to do.
Development
Design
Planning how a program will meet its requirements before building it.
Development
Prototype
An early version of a program used to test ideas and gather feedback.
Development
Documentation
Written descriptions that explain how and why a program works.
Development
Comment
A note in code, ignored by the computer, that explains the code to people.
Development
Logic error
A mistake in the algorithm that causes incorrect or unexpected results.
Errors
Syntax error
A mistake in a program's grammar that usually prevents it from running.
Errors
Run-time error
An error that occurs while a program is running, causing it to stop.
Errors
Overflow error
An error caused when a value is too large to be represented with the available bits.
Errors
Debugging
The process of finding and fixing errors in a program.
Errors
Testing
Running a program with varied inputs to reveal errors and verify behavior.
Errors
Test case
A specific input with a known expected output, used to check part of a program.
Errors