User Guide

++ (increment) 27
++ (increment)
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-increment and post-increment unary operator that adds 1 to
expression. The expression can be a variable, element in an array, or property of an object.
The pre-increment form of the operator (
++expression) adds 1 to expression and returns the
result. The post-increment form of the operator (
expression++) adds 1 to expression and
returns the initial value of
expression (the value prior to the addition).
The pre-increment form of the operator increments
x to 2 (x + 1 = 2) and returns the result
as
y:
var x:Number = 1;
var y:Number = ++x;
trace("x:"+x);//traces x:2
trace("y:"+y);//traces y:2
The post-increment form of the operator increments x to 2 (x + 1 = 2) and returns the original
value of
x as the result y:
var x:Number = 1;
var y:Number = x++;
trace("x:"+x);//traces x:2
trace("y:"+y);//traces y:1
For more information, see “Operator precedence and associativity” in Using ActionScript in Flash.
Example
The following example uses ++ as a post-increment operator to make a while loop run five times:
var i:Number = 0;
while (i++<5) {
trace("this is execution "+i);
}
/* output:
this is execution 1
this is execution 2
this is execution 3
this is execution 4