ActionScript: The Definitive Guide

Numeric Literals

We learned earlier that a literal is a direct representation of a single, fixed data value. The number type supports three kinds of literals: integer literals, floating-point literals, and special numeric values. The first two literal categories represent real numbers (numbers that have a fixed mathematical value); the third category comprises values that represent numeric concepts such as infinity.

Integer Literals

Integer literals such as 1, 2, 3, 99, and -200, must follow these rules:

• Integers may not contain a decimal point or fractional value.

• Integers must not exceed the minimum or maximum legal numeric values of ActionScript. See also the MIN_VALUE and MAX_VALUE properties of the Number object in Part III, for a discussion of legal values.

• Base-10 integer numbers must not start with a leading zero (e.g., 002, 000023, and 05).

Not all integer values are base-10 (i.e., decimal) integers. ActionScript also supports base-8 (octal) and base-16 (hexadecimal) numeric literals. For a primer on decimal, octal, and hexadecimal numbers, see:

http://www.moock.org/asdg/technotes

We use a leading zero to indicate an octal number. For example, to represent the octal number 723 in ActionScript, we use:

0723  // 467 in decimal (7*64 + 2*8 + 3*1)

To indicate a hexadecimal (hex for short) literal integer, we put 0x (or 0X) in front of the number, such as:

0x723  // 1827 in decimal (7*256 + 2*16 + 3*1)
0xFF   //  255 in decimal (15*16 + 15*1)

Hexadecimal numbers are often used to ...