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Functions
A function is a named unit, in which statements are logically grouped. It usually contains the following parts:
- Function Name - e.g. function someName( )
- Argument list - is enclosed within parentheses after the function name. It contains a comma-separated list of 0 or more arguments. Arguments are passed to the variable with the same name as the argument inside the function.
- Return Type - the datatype of what the function can evaluate to.
- The function Body - is enclosed within a pair of braces { } and contains a sequence of statements.
Function functionName(arg1, arg2, arg3){ // statements go here return something if not void return type; }example1 (AS 1.0). Type this and compile (Control+Enter):
function test1(arg1, arg2){ // arg1 is passed to the variable with the same name // in the next line I.e. arg1 trace(arg1); trace(arg2); } // call function test1(3,"Steve");Notice that to call a function we write the function name and the argument lists in parentheses. Template to call a function:
functionName(arg1, arg2);Example 2 with a return value (AS 1.0)
function returnTest(arg1){ var num = arg1 * 10; return num; } // call function trace(returnTest(5));ex. 3
// returns the absolute value of number function abs(number){ return( i < 0 ? -i : i); } // call the method trace(abs(-350.95); ex 4 // return the smaller of two values. function min(num1,num2){ return(num1 <= num2 ? num1: num2); } trace(min(27,45));
Functions in AS 2.0
Functions in AS 2.0 are a little different. AS 2.0 allows the setting of specific datatypes.
Here is an example :
Function avgReturn(arg1:Number):Number{ Var num = arg1 * 5; return num; }The template for an AS 2.0 function could be :
Function functionName(arg1:DataType, arg2:DataType):ReturnType{ // statements go here return something ; }Void is used to specify that there is no return type. E.g.
function noReturn(arg1:Number, arg2:String):Void{ trace(arg2+" is a string and "+arg1+" is a number"); } // call function noReturn(5,"Steve");
Arrays
An array is a collection of objects . Individual objects are not named but accessed by its position in the array.
Try this!
var theArray = new Array(5,4,8,2,1); for(var i = 0;i<5;i++){ trace(theArray[i]); }Elements are numbered beginning with "0".
In the above array
theArray[0] = 5
theArray[2] = 8
Length is a property of Array. It tells how many elements are in the array. So , from above,
theArray.length = 5
Classes
(As 2.0 only)
A class is a user-defined datatype, an aggregate of named data elements, and a set of operations to manipulate that data.
A class definition consists of two parts:
- The class head - composed of the keyword class and a name
- the class body - enclosed by braces, contains the member definitions
class Dog{ // data members var name:String; var age:Number; // class method function setAge(age1:Number){ age = age1; } }Constructors allow us to create an instance of a class . e.g.
var rusty:Dog = new Dog(); // the dot operator (".") // allows us to access members and methods of that class. rusty.setAge(7); rusty.name = "Rusty";
For more information and tutes , go to my site.
» Level Basic |
Added: 2005-08-10 Rating: 8 Votes: 12 |
» Author |
Steve Happ is the founder of Steve's Tutes and has been going hard at it developing Flash for Web and CD-rom. |
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