Static modifier in php

• Behaviors related to the class generally
• Not tied to a particular instance
• "class properties","class methods"
• Accessible directly from the class,without any instance
• use keyword static

Example

<?php
class Student{
static $grades=['Fresher','Junior','Senior'];
static function motto(){
return 'to learn php';
}
}

1.  Different syntax to reference static properties and methods
2. Student::$grades,Student::motto()
3. static methods cannot use $this
4. self::$grades,self::motto()
5. can be combined with visibility modifiers

Example:

<?php
class Student{
public static $grades=['Fresher','Junior','Senior'];
private static $total_students=0;
public static function count(){
return self::$total_students;
}
}
echo Student::grades[0];//Fresher
echo Student::$total_students;//error:cannot access private property
echo student::count();//0

• staic properties are not accessible from an instance
• static methods are accessible from an instance
• Bad practice:php5 warning,php7 deprecation notice

File:static_modifiers.php

<?php
class Student{
public static $grades=['Fresher','Junior','Senior'];
private static $total_students=0;
public static function motto(){
return 'to learn php';
}
public static function count()
{
return self::$total_students;
}
public static function add_student()
{
return self::$total_students++;
}
}
echo Student::grades[0].'<br>';
echo Student::motto().'<br>';
//echo Student::$total_students.'<br>';//error
echo Student::count().'<br>';
Student::add_students();
echo Student::count().'<br>';
?>