AP® Computer Science A

Flashcards

149 cards with the terms and ideas you need to know cold. The ones you find hard come back sooner.

Multiple choice practice

264 exam-style questions, timed like the real exam, with every answer explained.

Practice exam

The whole multiple choice section: 42 questions in 1 hour 30 minutes, weighted by unit like the real exam. A fresh mix every time.

Must-know sheet

The facts, rules and terms to know cold on exam day, on one page. Filter it by unit, or print it.

Free-response practice

20 free-response questions like the ones on the exam. Score your answer with the rubric and a model answer, or sign in for free AI scoring.

Using Objects and Methods

15 topics · 81 videos

• A program is an algorithm written in a language the compiler can check and the computer can run
• Every variable has a type, and the type decides what values it can hold and what operations work on it
• int division throws away the remainder, so the types in an expression change the answer
• Methods let you use code by knowing what it does, not how it does it
• Objects are instances of classes, and variables hold references to them

Selection and Iteration

12 topics · 60 videos

• Every algorithm is built from three moves: doing steps in order, choosing between paths, and repeating
• Boolean expressions decide which code runs and how long a loop keeps going
• De Morgan's laws turn a negated condition into an equivalent one
• Most loop bugs are off-by-one errors or conditions that never become false
• Tracing code line by line is the surest way to know what it does

Class Creation

9 topics · 52 videos

• Abstraction hides details so you can focus on what a class or method does
• Encapsulation keeps instance variables private and exposes behavior through methods
• A constructor sets an object's initial state
• Object parameters pass a copy of the reference, so methods can change the original object
• Programs affect people, so programmers have legal and ethical responsibilities

Data Collections

17 topics · 92 videos

• An array has a fixed size, while an ArrayList can grow and shrink
• Traversing a collection with a loop is the base of almost every algorithm here
• Removing items while traversing an ArrayList needs care to avoid skipping elements
• A 2D array is an array of rows, usually traversed in row-major order
• Binary search and merge sort repeatedly cut a problem in half
• Data can be biased or incomplete, and collecting it puts people's privacy at risk