AP COMPSCI PRINCIPLES

syntax error

A mistake in typed code that violates the rules of the programming language. (Code won't run because it's written wrong.)

logic error

A mistake in an algorithm or program that causes it to behave unexpectedly. (Code runs but gives wrong results.)

run-time error

A mistake that happens while the program is running. (Code crashes while it’s working.)

overflow error

Error from a number being too big to store. (Like a car’s odometer rolling over.)

bit

A binary digit, 0 or 1. (Smallest unit of data.)

byte

A group of 8 bits. (Basic chunk of data.)

roundoff

Error from not enough bits to show a number exactly. (Losing digits like turning pi into 3.14.)

analog data

Smooth, continuous values. (Changes like sound or light.)

lossless

Compression that keeps all data. (Nothing lost.)

lossy

Compression that loses some data. (Can’t get the original back exactly.)

metadata

Data about other data. (Info like file name or date created.)

Algorithms and Programming

sequencing

Steps done in order. (Like a recipe.)

selection

Choosing between options using a condition. (Like “if this, do that.”)

iteration

Repeating steps. (Like looping.)

linear search

Checking each item one-by-one. (Look through the whole list.)

binary search

Searching a sorted list by cutting it in half repeatedly. (Faster than linear.)

reasonable time

Program finishes in a decent amount of time. (Not super slow as input grows.)

heuristic

A shortcut method to get a good-enough solution. (Not perfect but works fast.)

undecidable

A problem with no possible algorithm to solve all cases. (Like the halting problem.)

library

A collection of pre-written code. (Tools you can use.)

API

A guide to using a library. (Tells you what functions are available and how to use them.)

modularity

Breaking code into parts. (Each part does one job.)

traversal

Going through a list. (Look at each item in a list.)

How the Internet Works

computing device

Anything that runs a program. (Phone, laptop, smart sensor, etc.)

computer network

Devices connected to share data. (Like the internet.)

bandwidth

How much data can go through a network. (Like the size of a pipe.)

protocol

Set of rules for communication. (Everyone follows the same rules to talk.)

scalability

System grows to meet more demand. (Can handle more users or data.)

IP (Internet Protocol)

Rules for addressing and sending data. (Finds the best path to send info.)

TCP

Reliable data delivery protocol. (Makes sure everything arrives correctly.)

UDP

Fast but less reliable data delivery. (Used for things like video calls.)

World Wide Web

System of linked content online. (The part of the internet with websites.)

HTTP

The web’s main communication rule. (Used to get and send website data.)

parallel computing

Doing many tasks at the same time. (Makes things faster.)

speedup

How much faster parallel computing is. (Time saved with multitasking.)

distributed computing

Many computers working together. (Split the job across devices.)

Impact of Computing

digital divide

Unequal access to technology. (Some people can't get online easily.)

crowdsourcing

Getting help or ideas from lots of online people. (Like Kickstarter or Wikipedia.)

citizen science

Public helps with science projects. (Volunteers collect data or report findings.)

Creative Commons

Lets creators share work with rules. (Choose how others can use your work.)

open access

Free public access to info. (No paywall for research or data.)

PII

Info that can identify someone. (Like name, ID, or address.)

multifactor authentication (MFA)

Using two or more ways to prove who you are. (Like password + code sent to phone.)

encryption

Scrambling data to protect it. (Makes it unreadable without the key.)

symmetric encryption

Same key to lock and unlock. (One shared secret.)

public key encryption

One key locks, a different key unlocks. (Safer for sharing.)

cookie

Small file websites use to remember you. (Tracks preferences or logins.)

virus

Malware that copies and spreads. (Can infect many files or systems.)

phishing

Trick to steal info. (Fake email asking for passwords.)

rogue access point

Fake Wi-Fi to spy on users. (Looks real but it’s a trap.)