AP Computer Science Principles Full Study Guide

Effective Collaboration

Avoids bias and produces innovations that reflect diversity of talents and perspectives

Computing Innovation

Includes a program as an integral part of its function and can be physical or non-physical software or concepts; solve problems or pursue interests through creative expression

Hardware

Physical components of a computing device

Inputs

Data sent to a computer for processing by a program through tactile, audio, visual, text, etc. to affect the output; can come from user or other program

Event

Generated when a defined action occurs and are associated with an action

Event-Driven Programming

Program statements that get executed when triggered rather than running in a sequential flow

Outputs

Data sent from a program to a device through tactile, audio, visual, text, etc.

Program/Software

Collection of program statements that perform a specific task when run by a computer; can be described broadly (what it does) or detailed (what it does and how it does it)

Code Segment

Portion of a program that performs a dedicated task

Development Process

Investigating and reflecting, designing, prototyping, and testing that requires refinement and revision throughout the process

Iterative and Incremental Development

A program design process that builds a program in small, tested parts (incremental) while constantly refining them through cycles of feedback and testing (iterative); Allows programmers to identify errors as components are added to a program

Investigation

Understanding/identifying program constraints, concerns, and purpose through data surveys, user testing, interviews, and direct observations

Program Requirements

Outlined in program specifications; describe how a program functions and may include a description of user interactions

Design Phase

How to accomplish a given program specification; done through brainstorming, storyboarding, breaking up into modules, diagrams, and coming up with strategies

Testing

Done at micro and macro level to identify needed revisions

Load Testing

Simulating high amounts of traffic in a short period of time to see if a system crashes/buckles under the load

Acknowledgment

Code segments from outside collaborators or sources must be acknowledged in program’s documentation

Program Documentation

Written description of function of a code segment, event, procedure, or program and how it was developed; Most often in comments and should be done throughout development

Logic Error

Mistake in the algorithm or program causing it to behave incorrectly or unexpectedly

Syntax Error

Mistake in the program where the rules of the programming language aren’t followed

Run-time Error

Mistake in program that occurs during the execution of a program

Roundoff Error

Produces a number that is too precise and must be simplified

Off-by-one Error

Common kind of logic error when dealing with indices and accidentally sue too high or low an index

Overflow Error

Mistake when a computer attempts to handle a number outside of the defined range of value; Produces a number that is too large for designated space and either gets capped or wraps around

Floating Point Representation

Typically used for non-integer real numbers in computer memory that uses scientific notation to handle a large range of values

Correcting Errors

Test cases, hand tracing, visualizations, debuggers, and extra output statements

Bit

Shorthand for binary digit and is either a 0 or 1 (on or off) that represent all digital data, where one bit is one unit of data

Alphanumeric Character

Anything on keyboard that can be on a computer

Bitmap

Mapping certain pixels to 0 and others to 1

Bit Rate

Number of bits of data that are sent per second; used to measure speed of network connections sending bits

Byte

8 bits often used to represent information in computers

Byte Pair Encoding

Replaces the most common pairs of characters with the outside character, making a table of replacement mappings

Run-length encoding (RLE)

Replaces “runs” or sequences of bits with the same value with a number representing the length of the run; popular technique for images with limited color palettes

Binary System

Uses bits with values that are powers of 2

Abstraction

Reduces complexity and allows programmers to focus on the main idea of a larger problem; Examples where digital data is used to approximate real world analog data

Analog

Mechanism, device, or technology that represents data by measurement of a continuous, physical variable; A continuous stream of varying data

Sampling

Measures the values of the analog signal at regular intervals to represent “smoothness” of a piece of analog data; Reduces continuous domain into a series of discrete intervals

Sampling Rate

Number of samples in a second (or other unit of time)

Quantization

Reduces the continuous amplitude domain into discrete intervals

Bit Depth

The number of bits per sample

Integers in Programming

Represented by a fixed number of bits (where limitation can occur) or only by the size of the computer’s memory

Binary

Base 2 that only uses a combination of 0 and 1

Decimal

Base 10 that only uses a combination of 0-9

Data Compression

Can reduce size (number of bits) of transmitted or stored data to save transmission time and storage space; Fewer bits does not always mean less information

Lossy Compression

Reduces size of files by discarding less important information; More size reduced but more information lost than comparable Lossless Compression

Lossless Compression

Reduces size of files without losing any information, allowing full reconstruction

Lossless Text Compression

Finds repeated sequences and replaces with shorter representations

Lossless Image Compression

Uses run-length encoding (RLE) and bitmap

Data Challenges

Need to clean or combine sources, and data can be incomplete or invalid

Cleaning Data

Process that makes the data uniform without changing their meaning

Problems of Bias

Often created by the type or source of data being collected; Bias not eliminated simply by collecting more data

Size of Data

Affects the amount of information that can be extracted from it; Large data sets are difficult to process using a simple computer and may require parallel systems

Scalability of Systems

Important as computational capacity (ability to manage, process, and scale to meet demands) of a system affects how data sets can be processed and stored

Information

Collection of facts and patterns extracted from data

Opportunities through Data

Identifying trends, making connections, and addressing problems

Metadata

Data about data used for finding, organizing, and managing information, allowing data to be structured and organizing, which can increase the effective use of data; changes to metadata doesn’t change primary data

Correlation

Variables tend to follow same relationship (increase/decrease at a similar rate) but aren’t causing each other

Causation

One variable directly causes change in another

Programs with Data

Used to process data to acquire information in iterative and interactive ways, through filtering or cleaning data, combining data sources, clustering data, and classifying data

User Interaction with Data

Filter, sort, combine, transform, cluster, or classify in order to gain more knowledge or insight; Can be communicated through tables, diagrams, texts, and other visual tools

Data Filtering Systems

Important tools for finding information and recognizing patterns

Processes for Data

Transforming, filtering, combining, comparing, or visualizing

Database

A system that stores data on a computer in a way that can be easily accessed, updated, queried, or deleted

Big Data Sets

So large that traditional ways of storing and processing data are no longer adequate; challenges include storage, processing, and responsible use

ASCII

First standardized encoding that transmits 128 characters into 7 bits for computer use; only has English alphabet and limited symbols

UTF-8

Encoding that is compatible with ASCII but solves its problems

Variable

Abstraction inside a program that can hold a value and change over time; each variable has a name, value, and type

Variable Names

Meaningful variable names help readability of program code

Data Types

Referenced using variables; include Booleans, Lists, Strings, Integers, etc.

Assignment Operator

Shown as ← on exam; changes the value represented by a variable

List

Ordered sequence of elements and related information

Append Items

Adding a new item to the end of the list

Inserting Items

Adding an item at a specific place in the list

Removing Items

Often uses splice() method to remove a specific item

Element

Individual value in a list assigned a unique index

Index

Common method for referencing list/string elements using natural numbers; starts at 1 on AP exam

String

Ordered sequence of characters

String Literals

Fixed sequence of characters within quotation marks

Character

Each letter or piece of a string

Data Abstraction

Hides representation details to simplify development and maintenance

Lists as Data Abstraction

Bundle variables together and treat multiple related items as one value

Sequencing

Applying algorithm steps in the correct order

Code Statement

Instruction carried out by the computer

Expression

Value, variable, operator, or procedure call evaluated to produce one value

Arithmetic Operator

Used to create mathematical expressions

Remainder or MOD operator

Calculates remainder of division

Mathematical Procedure and Constants

Advanced math functions/constants like absolute value or pi

String Concatenation

Joins strings together

Slicing Operator

Extracts part of a string

Substring

Part of an existing string

Boolean Value

Expression that evaluates to true or false

Relational Operators

Compare variables, expressions, or values

Logical Operators

AND, OR, NOT combine boolean expressions

Logical Equivalence

Different expressions with same meaning

NOT Operator

Negates truth value

AND Operator

Both conditions must be true

OR Operator

At least one condition must be true

Selection

Executes code based on a condition

Conditional/If Statements

Execute different statements based on boolean expression

Nested Conditional

Conditional statements inside other conditionals