AP CSP Abstraction

Abstraction

Creating simple concise representations of more complex phenomena so that people can more easily work with, communicate about, and learn about anything.

Analog

A continuous method of representing information.

Analog-to-Digital Conversion

A process of converting continuous information into discrete data; some information is typically lost.

ASCII

A standard code for representing text characters using one byte. Generally replaced by UTF-8 or UTF-16 to support international languages.

Base n

A base n number system has n digits and uses place values that are powers of n.

Binary

The binary number system is base 2, using only bits 0 and 1.

Bit

A single unit of binary consisting of only one place whose value can be 0 or 1.

Byte

Eight bits, able to represent 256 distinct values. Abbreviated "b".

Compression

Storing information using fewer bytes.

Compression Ratio

Summarizes the reduction in size of a file. Can be expressed two different ways, as follows. If more than 1, the compression ratio tells how many times bigger the original file is. If less than 1, the compression ratio tells the percentage by which the original file size has been reduced.

Concatenation

Attaching two things side-by-side, frequently strings of text.

Continuous

Varying smoothly from one value to another. Opposite of discrete.

Data Abstraction

Representing or storing information with methods that separate layers of concerns so that the programmer can work with information while ignoring lower-level details about how the information is represented.

Digit

A single number (0-9) used to represent numeric quantities in base 10.

Digital

Data which can only take on discrete values. Opposite of analog.

Discrete

Jumping from one value to another without taking on all intermediate values. Opposite of continuous.

Event Handler

A chunk of code that responds to actions performed by users or by other parts of the program.

Fidelity

The extent to which a copy is identical to the original.

Global Variable

A variable that can be used in any part of the program.

Hexadecimal

The hexadecimal number system is base 16, using only digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, and F.

Kilobyte

One thousand bytes (abbreviated "kb"). Sometimes used to mean 210 bytes = 1024 bytes (abbreviated "kib").

Megabyte

One million bytes ("Mb"). Sometimes used to mean 220 bytes = 1,048,576 bytes (abbreviated "Mib").

Lossy

Describes a method of compression in which data is lost in a way that cannot be recovered from the compressed data.

Octal

The octal number system is base 8, using only digits 0 through 7.

Palette

A limited set of colors.

Padding

Blank space placed around elements of a display to make it look the way the designer planned.

Pixel

A single dot in an image. Many color monitors actually have three dots (red, blue, and green) for each pixel, but it is referred to as one pixel.

Procedure Definition

Identify a chunk of code that will be reusable anywhere else in the program by calling its name

Pseudorandom

Numbers that are difficult to predict and created by a computer.

Type

A specific meaning for data, such as a character, a truth value, or an integer, usually limiting the values allowed for the data.

UTF-8

A coding system for storing characters in bits, extending the 8-bit ASCII coding system to include international characters by sometimes using more than 8 bits.