runestone academy ap csp unit 3

code statement

program code that expresses an action to be carried out

variable

-names a memory location to hold many values in a program -data abstraction (has associated data storage) -stores data in the computer's main memory (RAM) -data is volatile

get block

gets the variable's current value whenever needed in the program

set block

assigns or changes the value of the variable

assignment

sets a variable to a value or mathematical expression

display

displays variable values or values resulting from mathematical operators

expression

values, variables, math operators, and mathematical procedures that returns (evaluates) a single value

evaluation

set order of operations for expression defined by the programming language

operator

-a symbol or function representing a math operation

assignment operator

allows a program to change the value of a variable

relational operators

-used inside "if" statements to compare variables with values or math operators -evaluates to a Boolean value

bitmap (raster)

memory organization or image file format used to store digital images

bit

-binary digit -smallest unit of data -fewer bits does not mean less information

run-length encoding (RLE)

-compression algorithm that represents an image by the length of runs of identical pixels -lossless compression technique -used in bitmap (BMP) images

image compression

-Data compression that reduces the number of bits of transmitted or stored data -Size reduction depends on the number of bits/pixels, number of diff. colors in the image, amount of redundancy in the original data representation, and the application of the compression algorithm

American Standard Code for Information Interchange (ASCII)

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

lossless compression

-Data compression technique in which no data is lost i.e. RLE -Used in BMP images -Used when the quality/ability to reconstruct the image is important

lossy compression

-Data compression technique in which some data is lost i.e. JPEG -Greater size reduction than lossless compression -Used when minimization of data size/transmission time is important

pixel (picture element)

single point in a graphic image

data type

The type of data stored in a variable i.e. string, boolean, or list.

analog data

values that change smoothly, rather than in discrete intervals, over time (i.e. pitch and volume of music, colors of a painting, position of a runner)

samples

-values of the analog signal at regular intervals -measured to determine the number of bits required to store each sample

refactoring

-process of restructuring program code without changing its behavior -simplifies design, making it easier to read & maintain

procedural abstraction

-Organizing and encapsulating algorithms in named procedures that can be called by name -Makes program smaller, easier to read, and allows for code reuse -Form of refactoring -Allows programmers to change the internals of the procedure without needing to notify users of the change

program documentation

-Written description of the function of a code segment, event, procedure, or program and how it was developed -Helps in developing and maintaining correct programs

comment

-Non-executable block of text added to a program to provide clarification and documentation of the code -Can acknowledge code segments created collaboratively, by someone else, or by another source

bug

-error in computer hardware or software -coined by Grace Hopper.

debugging

process of removing errors from computer software/hardware

tracing

stepping through the program line by line and carefully recording what happens to spot the error

modularity

separation of a program into independent modules that are each responsible for one aspect of the program's functionality.

flipped bit

bit that switches from 1 to 0 or vice versa

parity

evenness or oddness of a number

parity bit (redundant bit)

-bit that acts on a set of binary values -added to the leftmost bit of a string of bits to ensure the number of bits are even or odd

even parity

number of 1s in the sequence add up to an even number

odd parity

number of 1s in the sequence add up to an odd number

list (array)

-stores multiple terms (elements) under one variable name and uses an index to number and access them in memory -data abstraction (abstract data type)

element

individual value in a list that is assigned a unique index

index

number or position of an element in a list from 1 to the length of the list (natural numbers)

string

Sequence of characters that can stored in variable or text

substring

a string that is part of a longer string

concatenation

putting 2 strings together to make a new string

abstract data type (ADT)

defines a general data type that describes a collection of data without worrying about the specific implementation (i.e. list)

Application Programming Interface (API)

-Defines how other programs/web services can use it and communicate with it -Specifies how procedures in a library behave and can be used

Global Positioning System (GPS)

allows people to pinpoint their geolocation (geographic location) on Earth using satellites.

database

-stores persistent data in the computer's long-term storage (i.e. TinyDB, Firebase)

volatile storage

stored data that is destroyed when exited

tag/value pairs

-stores data -tag has to be a string -value can be a number, string, or list that is stored & retrieved by their tag

data abstraction

-Separates the abstract properties of a data type and the concrete details of its representation -Manages complexity by giving a collection of data a name without referencing its specific details

algorithm

a step-by-step procedure for solving a particular problem.

cloud computing

shares resources online on the Internet rather than having data be located on a personal computer

digital

-system based on discontinuous data or events -computers are digital machines because they can distinguish between only 0's and 1's at the basic level

digital signal processing

manipulation of analog info

download

process of copying data (entire file) from an online source to a personal computer

megabyte

-unit of data characterization -roughly 1 million bytes (2<sup)

megapixel

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

model

representation of a photograph in bits

modeling

-process of representing a real-world object of phenomenon as a set of mathematical equations -process of capturing the representation of a photograph in bits -always omits information

optical character recognition (OCR)

process of reading text from paper & translating the images into a form that the computer can manipulate

rendering

-transferring of bits representing a digital photograph to a computer screen or printer -process of adding realism to computer graphics by adding 3D qualities i.e. shadows, variations in color & shade

spam

electronic junk mail/junk newsgroup postings

steganography

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

cryptography

-"secret writing" -protects information by transforming it into an unreadable format.

metadata

-Data about data -Used for finding, organizing, and managing information -Increases the effective use of data or data sets by providing additional information -Allows data to be structured and organized