(::) in php defined as Scope Resolution Operator. Just like a double colon. Normally Scope Resolution Operator used when we want to access Contstant, static and overriiden methods and properties of a class.
So, the summary is using (::) you can access properties and methods in a class without instantiated it. see example below:
<?php
class test{
public function hello(){
echo "Hello World \n";
}
}
echo test::hello(); //without instantiate class, using Scope Resolution Operator
$hello1=new test; // instantiate class, normal usage
$hello1->hello();
?>
But the main purpoe of using Scope Resolution Operator(::) is when we want to access Contstant, static and overriiden methods and properties of a class. see example below:
<?php
class test{
const PI=3.1416;
static $i=6;
}
echo test::PI; //constant property
echo test::$i; //static property
?>
Now to access class properties inside method , we need to use self. see example below:
<?php
class test{
const PI=3.1416;
static $i=6;
static function show(){
echo self::PI; //using self to access class properties
echo ' ';
echo self::$i;
}
}
echo test::show();
?>
In another case, if your method is overridden by child class and you need to call the parent class method just use parent keyword. see the example below:
<?php
class test{
public function hello(){
echo "Hello World \n";
}
}
class mytest extends test{
public function hello(){
parent::hello(); //using parent to access parent class method
echo "Hello beautiful world";
}
}
$world1 = new mytest();
$world1->hello();
?>
Thnak you and enjoy :)