Introduction
In this article I will explain static variables in PHP. A static variable is a variable that has been allocated statically. Static variables only exist within a local scope and it retains its previous value even after function calls; static variables are initialized only one. Static variables can be used wiih recursive functions.
Example
Static Variable with Recursive Function
<?php
function test()
{
static $count=0;
$count;
return $count;
if($count<10)
{
test();
}
$count--;
}
?>
This example does not return a value.
Declare Static Variable
<?php
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;
}
?>
Example2
<?php
function testfun()
{
static $value = 0;
$value += 1;
return $value;
}
testfun();
testfun();
testfun();
testfun();
echo testfun() ."<br>";
?>
In the example above, I have used a simple non-static variable and incremented the variable each time the function is called. We call the function five times. After five function calls $value is equal to 1.
Output
![static variable.jpg]()
The static variable function is initialized only one time, when the function is the first called. They retain their value afterwards.
Example
<?php
function staticf()
{
static $value = 0;
$value += 1;
return $value;
}
staticf();
staticf();
staticf();
staticf();
echo staticf(). "<br>";
?>
Output
![static variable.jpg]()
After five consecutive calls $value is equal to 5.