User Guide

–– (decrement) 81
–– (decrement)
Availability
Flash Player 4.
Usage
––expression
expression––
Parameters
expression
A number or a variable that evaluates to a number.
Returns
A number.
Description
Operator (arithmetic); a pre-decrement and post-decrement unary operator that subtracts 1 from
the
expression. The expression can be a variable, element in an array, or property of an object.
The pre-decrement form of the operator (
––expression) subtracts 1 from expression and
returns the result. The post-decrement form of the operator (
expression––) subtracts 1 from the
expression and returns the initial value of expression (the value prior to the subtraction). For
more information, see “Operator precedence and associativity” on page 32.
Example
The pre-decrement form of the operator decrements x to 2 (x - 1 = 2) and returns the result as y:
var x:Number = 3;
var y:Number = --x;
//y is equal to 2
The post-decrement form of the operator decrements x to 2 (x - 1 = 2) and returns the original
value of
x as the result y:
var x:Number = 3;
var y:Number = x--;
//y is equal to 3
The following example loops from 10 to 1, and each iteration of the loop decreases the counter
variable
i by 1.
for (var i = 10; i>0; i--) {
trace(i);
}
CHAPTER 5
ActionScript Core Language Elements