AP Computer Science Principles

Agile software development

An approach to software development that emphasizes a flexible and ready response to meet a shifting target.

Benchmarking

Running a program on many data sets to be sure its performance falls within required limits; timing the same algorithm on two different machines.

Code library

A collection of thoroughly tested object code for various useful tasks.

Coding

The process of translating the detailed designs into computer code.

Divide-and-conquer

A program design strategy in which tasks are broken down into subtasks, which are broken down into sub-subtasks, and so on, until each piece is small enough to code comfortably. These pieces work together to accomplish the total job.

Empirical testing

Designing a special set of test cases and running the program using these test data.

External documentation

Any materials assembled to clarify the program's design and implementation.

Feasibility study

A step in the software development life cycle that evaluates a proposed project and compares the costs and benefits of various solutions.

Integrated development environment (IDE)

A collection of programs that support software development, such as debuggers, editors, toolkits, and libraries, that lets programmers perform several tasks within the shell of a single application.

Internal documentation

Documentation that is part of the program code itself.

Logic error

An error in the algorithm that causes unintended results; results are different than what the programmer had wanted

Object code

Machine language instructions.

Pair programming

Involves two programmers at a single workstation. At any given point in time, one is writing code and the other is actively observing, watching for possible errors

but also thinking about the overall approach.

Problem specification

A step in the software development life cycle that involves

developing a clear, concise, and unambiguous statement of the exact problem the software

is to solve.

Procedural language

A program written in a procedural language consists of sequences of statements that manipulate data items.

Program design phase

A step in the software development life cycle that plans the structure of the software to be written.

Program maintenance

The process of adapting an existing software product due to errors, new system requirements, or changing user needs.

Program verification

Used to prove that if the input data to a program satisfies certain conditions, then, after the program has been run on these data, the output data satisfies certain other conditions.

Runtime error

An error that occurs when the program is run using certain sets of data that result in some illegal operation, such as dividing by zero.

Semantics

The meaning of correctly written programming statements.

Source code

High-level language instructions.

Syntax error

An error that occurs because a program statement fails to follow the correct

rules of syntax.

Technical documentation

Documentation that enables programmers who later have to modify the program to understand the code.

Third-generation language

Another name for high-level programming language as

opposed to machine language (first generation) or assembly language (second generation).

Top-down decomposition

A program design strategy in which tasks are broken down into subtasks, which are broken down into sub-subtasks, and so on, until each piece is small enough to code comfortably. These pieces work together to accomplish the total job.

Syntax

The rules for exactly how programming statements must be written; the grammatical structure of a programming language

Application

(Java) A complete standalone program that resides and runs on a self-contained computer.

External library

A well-written, efficient, and thoroughly tested code module that is separately compiled and then drawn on by any program that wishes to use its capabilities.

Functional programming languages

Views every task in terms of functions. In this context, function means something like a mathematical function—a recipe for taking an argument (or possibly several arguments) and doing something with them to compute a single value.

Knowledge base

Facts and rules about a certain domain of interest.

Open source

Software whose source code is freely available and may be used, distributed, or modified by anyone.

Recursive

Something that is defined in terms of "smaller versions" of itself.

Computational model

A model constructed using algorithmic procedures implemented as computer programs.

Computer graphics

The field of computer science that examines the technical problems of displaying visual images on a computer screen.

Garbage in, garbage out

The term for the fact that the output coming out of a computer model is only as accurate as the assumption used to build the model.

Scientific visualization

The use of images and visualization techniques to make scientific data easier to interpret and understand.

Simulation model

Another term for a computational model.

Uniform random number

Every value in the range from a to b has the same chance of occurring.

Analogy

Arguing about a problem by comparing it to a related problem, which you claim is very similar in terms of its ethical implications and consequences.

Cyberbullying

Humiliating, taunting, threatening or invading someone's privacy using the Internet, Web, or other type of electronic technology.

Ethics

The study of how to decide if something is morally right or wrong.

Hacktivism

Hacking that is intended as political activism.

Peer-to-peer file sharing

The sharing of files between two equal participants on a network. This is distinct from the client-server model in which the two sides serve very different roles--one side only sending information (the server) and the other side only receiving information (the client).

Computer science

The study of algorithms, including their mathematical properties, hardware and linguistic realizations, and their applications.

Computing agent

The entity (machine, robot, person, or thing) that executes the steps of an algorithm.

High-level programming language

A programming language that uses both natural language constructs and mathematical notation. This kind of language is the easiest for humans to read and understand.

Infinite loop

The repetitive execution of a block of operations that will never end. This is a fatal error when it occurs in an algorithm.

Sequential

An algorithmic operation that carries out a single task and then moves on to the next operation in sequence. Also a type of search where you search for an item in a list by starting with the first item and looking at each subsequent item in order.

Algorithm discovery

The process of finding an algorithmic solution to a given problem.

Computation

An algorithmic operation that carries out a single numeric computation and stores the result.

Conditional statements

Operations that ask a question and select the next instruction to carry out based on the answer to that question.

Continuation condition

The true/false condition that will determine when the iteration has been completed.

Control operations

Operations that alter the normal sequential flow of control within an algorithm. Ex: if statements

Input

An operation that causes data values from the outside world to be brought into the algorithm.

Iteration

The repetitive execution of a block of operations.

Output

An operation that causes computed values to be sent to the outside world for viewing or saving.

Pseudocode

A notation used to design algorithms. It uses English constructs, mathematical notation and an informal algorithmic structure designed to look like a high-level programming language.

Sorting

The task of putting a list of values into numeric or alphabetical order.

Boolean expression

An expression that can evaluate only to true or false.

Gigabyte

One billion bytes.

Program

an algorithm that is written in a programming language that runs on a computer

Control Structures

a block of programming that determines which part of the program is executed next. There are three types of structures: sequence, selection, and repetition.

Computational Artifact

an object created by a human being that involves the use of computation in some way, for example a mobile app or a web page.

Event Driven Programming

a programming approach whereby the program's behavior is controlled by writing code that responds to various events that occur, such as Button clicks.

Hardware

the large and small physical components that make up a computers such as the computer's keyboard or its processor.

Software

the computer programs that make up a computer system such as the mobile apps we will be creating in this course.

Abstraction

one of the seven big ideas of the CS Principles curriculum. An abstraction is a simplified and general representation of some complex object or process. One example --we'll encounter many in this course, including abstractions used in computer programming -- would be a Google map.

Binary Number

a number written in the binary system, a system that uses only two digits, 0s and 1s.

Blacklist

in internet terminology, a generic term for a list of email addresses or IP addresses that are origination with known spammers

Character

any symbol that requires one byte (8 bits) of storage

Cyberspace

a metaphor for describing the non-physical terrain created by computer systems

Data

data is distinct information that is formatted in a special way. Data exists in a variety of forms, like text on paper or bytes stored in electronic memory

Data Center

are physical or virtual infrastructures used by enterprises to house computer, server and networking systems and components for the company's IT (information technology) needs

Data Network

a telecommunications network which allows computers to exchange data

Disk Drive

a randomly addressable and rewritable storage device

Intellectual Property

refers to any property that is created using original thought. Traditional intellectual property include patents, copyrights, and trademarks.

Network

a group of two or more computer systems linked together

Processor

short for microprocessor or CPU

Social Networking

a social structure made of nodes that are generally individuals or organizations. A social network represents relationships and flows between people, groups, organizations, animals, computers, or other information/knowledge processing entities

Whitelist

a generic name for a list of email address or IP addresses that are considered to be spam free

Analog

a device or system that represents changing values as continuously variable physical quantities ex. sound waves

ASCII

a code for representing English characters as numbers, with each letter assigned a number from 0 to 127

Cloud Computing

comparable to grid computing, cloud computing relies on sharing resources rather than having local servers handle applications.

Cryptography

the art of protecting information by transforming it into an unreadable format, called cipher text

Digital

any system based on discontinuous data or events. Computers are digital machines because at the basic level they can distinguish between just two values, 0 and 1.

Digital Signal Processing

(DSP) refers to manipulating analog information

Download

to copy data (usually an entire file) from a main source to a peripheral device

Megabyte

used to describe data storage, 1,048,576 bytes (abbreviated MB)

Megapixel

one million pixels, used in reference to the resolution of a graphics device

Modeling

process of representing a real-world object of phenomenon as a set of mathematical equations.

Raster

the rectangular area of a display screen actually being used to display images

Render

refers to the process of adding realism to a computer graphics by adding 3-D qualities, such as shadows and variations in color and shade.

Spam

spam is electronic junk mail or junk newsgroup postings

Steganography

the art and science of hiding information by embedding messages within other, seemingly harmless messages

Upload

to transmit data from a computer to a bulletin board service, mainframe, or network.

Bit

Single unit of information on a computer represent as a 0 or 1

Bit Rate

The number of bits that are conveyed or processed per unit of time

Latency

The time it takes for a signal to arrive

Bandwidth

Transmission capacity, measured by bit rate

Fiberoptics

Method of transmitting data that utilizes light