MACROMEDIA FLASH 8-LEARNING ACTIONSCRIPT 2.0 IN FLASH, Руководство пользователя

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216 Functions and Methods
Anonymous functions are often more difficult to read. Compare the following code to the
preceding code.
var myCircle:Function = function(radius:Number):Number {
// function block here
return (Math.PI * radius * radius);
};
trace(myCircle(5));
You can also place functions in class files when you use ActionScript 2.0, as the following
example shows:
class Circle {
public function area(radius:Number):Number {
return (Math.PI * Math.pow(radius, 2));
}
public function perimeter(radius:Number):Number {
return (2 * Math.PI * radius);
}
public function diameter(radius:Number):Number {
return (radius * 2);
}
}
For more information on writing functions in a class file, see Chapter 7, “Classes,” on
page 225 .
As you can see in the previous code sample, you don’t need to place functions on a timeline.
The following example also puts functions in a class file. This is a good practice to adopt
when you create large applications by using ActionScript 2.0, because it lets you reuse your
code easily in several applications. When you want to reuse the functions in other
applications, you can import the existing class rather than rewrite the code from scratch or
duplicate the functions in the new application.
To create functions in a class file:
1. Create a new ActionScript document and save it as Utils.as .
2. Type the following ActionScript into the Script pane:
class Utils {
public static function randomRange(min:Number, max:Number):Number {
if (min > max) {
var temp:Number = min;
min = max;
max = temp;
}
return (Math.floor(Math.random() * (max - min + 1)) + min);
}
public static function arrayMin(num_array:Array):Number {
if (num_array.length == 0) {