Datatypes, Variables, Constants

Flash Class

What Does ActionScript Do?

• Automates• Examples:– Tells animation what to do button is clicked– Turn off sound

• Designer “scripts” different parts of the animation

• Examples: tell the animation to load a Web page upon clicking a link

Building Blocks

Flash• Flash animations made up

of:– Drawings– Text– Frames (hold drawings, text)– Timelines (hold frames)

ActionScript 3• ActionScript made up of:

– Numbers– Strings

• Building blocks for more complicated data containers

ActionScript Building Blocks

• Numbers

• Strings

• Arrays

Numbers

• Numbers are an important data-building block• So important there are three types:– number– int (integer)– uint (unsigned integer)

Review Terms

• Integer: in computer science, an integer is used to refer to a data type which represents some finite subset of the mathematical integers. These are also known as integral data types.

• In programming languages a data type is an attribute of a datum which tells the computer (and the programmer) something about the kind of datum it is. This involves setting constraints on the datum, such as what values it can take and what operations may be performed upon it. Common data types may include: integers, floating-point numbers (decimals), and alphanumeric strings.

Numbers: Number

• In ActionScript, a number can be any type of number, including fractions

• Example: 2.5

int

• The int datatype can represent any number from -2,147,483,648

to

2,147,483,648

It cannot represent fractions. Use Number.

uint

• Unsigned integer

• Can represent numbers from 0 to4,294,967,295

• Use if you need a negative number

• Useful when identifying colors, especially since colors are always positive whole numbers

Using Operators

Examples of Operators• +• -• *• /• >• <• >=

Examples of Operators

• <=• ==• !=• =• See Operators at Adobe.• For more.

Strings

• Strings are sequential lists of letters, numbers, and symbols.

• Identify strings by placing them inside single or double quotes.

• Example: myCar + “Stutz Bearcat”

Strings and Operators

• Can’t do math with strings

• Concatenation (looks like string addition)

• Example: carModel = “Stutz” + “ “ + “Bearcat”;

Differences in Equality Operator (==) and Assignment Operator (=)

Equality Operators• Used to make a statement:

• The data on the right side of the equality operator is equal to the data on the left

• Statement may be true or false

Assignment Operator• Changes the value of the

variable on the left

Boolean

• Definition: Boolean has one of two values, true or false

• Used when programs test conditions, then report back