++ (increment)
SWiSH Player Support
SWF4 or later - Supported Internally
Syntax
++expression
expression++
Arguments
expression can be a variable, number, element in an array, or the property of an Object.
Returns
++expression returns expression + 1.
expression++ returns expression.
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, x 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, x is equal to 2
Sample
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()); // displays "1,2,3,4,5,6,7,8,9,10" in the 'Debug' window
The following example uses ++ as a post-increment operator .
var a = [];
var i = 0 ;
while (i < 10 ) {
a.push(i++);
}
trace(a.join()); // displays "0,1,2,3,4,5,6,7,8,9" in the 'Debug' window.