++ (increment)

Availability

Flash Player 4.

Usage

++expression
expression++

Parameters

None.

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:

x = 1;
y = ++x
//y is equal to 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:

x = 1;
y = x++;
//y is equal to 1

Example

The following example uses ++ as a post-increment operator to make a while loop run five times.

i = 0;
while(i++ < 5){
trace("this is execution " + i);
}

This example uses ++ as a pre-increment operator.

var a = [];
var i = 0;
while (i < 10) {
  a.push(++i);
}
trace(a.join());

This script displays the following result in the Output panel:

1,2,3,4,5,6,7,8,9,10

The following example uses ++ as a post-increment operator.

var a = [];
var i = 0;
while (i < 10) {
a.push(i++);
  }
trace(a.join());

This script displays the following result in the Output panel:

0,1,2,3,4,5,6,7,8,9