MACROMEDIA FLEX-FLEX ACTIONSCRIPT LANGUAGE, Справочник

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–– (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