St Patrick Day PHP How to use static variables

Take a look at the following example:

Copy the Code code as follows:

function Test ()
{
$w 3sky = 0;
echo $w 3sky;
$w 3sky++;
}
?>

Each call to this function sets the value of $w 3sky to 0 and outputs "0". Adding a variable to the $w 3sky++ has no effect, because once exiting this function the variable $w 3sky does not exist. To write a count function that does not lose this count value, define the variable $w 3sky as static (static):
As follows:

Copy the Code code as follows:

function Test ()
{
static $w 3sky = 0;
echo $w 3sky;
$w 3sky++;
}
?>

Each call to test () of this function outputs a value of $w 3sky and adds one.
Static variables also provide a way to handle recursive functions. A recursive function is a method of calling itself. Be careful when writing recursive functions, as there may be infinite recursion and no exits. Be sure there is a way to abort recursion. The following simple function recursively counts to 10, using a static variable $count to determine when to stop:
Examples of static variables and recursive functions:

Copy the Code code as follows:

function Test ()
{
static $count = 0;
$count + +;
Echo $count;
if ($count < 10) {
Test ();
}
$count--;
}
?>

Note: Static variables can be declared according to the example above. If you assign a value to a declaration with the result of an expression, it causes a parse error.
Example of declaring a static variable:

Copy the Code code as follows:

function foo () {
static $int = 0;//correct
static $int = 1+2; Wrong (as it is an expression)
Static $int = sqrt (121); Wrong (as it is an expression too)
$int + +;
Echo $int;
}
?>

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