ActionScript for Flash MX: The Definitive Guide, Second Edition

This is the Title of the Book, eMatter Edition

Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.

82

|

Chapter 4: Primitive Datatypes

Number.MAX_VALUE comes in handy when we are checking to see if a calculation results

in a representable number:

z = x*y;

if (z <= Number.MAX_VALUE && z >= –Number.MAX_VALUE) {

// Number is legal

}

Note that Number.MIN_VALUE is the smallest positive value allowed, not the most nega-

tive value. The “largest” negative legal value is

–Number.MAX_VALUE.

Infinity and negative infinity: Infinity and -Infinity

If a calculation results in a value larger than Number.MAX_VALUE, ActionScript uses the

keyword

Infinity to represent the result of the calculation (this is known as an over-

flow condition). Similarly, if a calculation results in a value more negative than the

“largest” allowable negative value, ActionScript uses

–Infinity to represent the result

(this is known as a negative overflow condition).

Infinity and –Infinity can also be

used directly as literal numeric expressions.

Irrational numbers

In addition to the special numeric values—NaN, Infinity, –Infinity, Number.MAX_VALUE,

and

Number.MIN_VALUE—ActionScript provides convenient access to mathematical con-

stants via the Math object. For example:

Math.E // The value of e, the base of the natural logarithm

Math.LN10 // Natural logarithm of 10

Math.LN2 // Natural logarithm of 2

Math.LOG10E // Base-10 logarithm of ...