PHP

PHP OPERATORS:-

Operators are used to perform operation on variable and values.

PHP have the 7-Operators :-

• Arithmetic Operator
  
• Assignment Operator
  
• Comparison Operator
  
• Increment/Decrement Operator
  
• Logical Operator
  
• String Operator
  
• Array Operator
  

PHP Arithmetic Operator:-

PHP Arithmetic Operator are used with numeric value to perform arithmetic operation like:- Addition, Subtraction, Multiplication, Division, Remainder ..

Opertaor	Name	Example	Result
+	addition	$x + $y	Sum of $x and $y
-	Subtraction	$x - $y	Difference of $x and $y
/	Division	$x / $y	Division of $x and $y
*	Multiplication	$x * $y	Multiplication of $x and $y
%	Modulus	$x % $y	Remainder of $x and $y
**	Exponentiation	$x ** $y	Raising $x to the $y'th power

PHP  Assignment Operator:-

PHP assignment operator is used with numeric value to assign value of one variable to other variable.

Opertaor	Name	Example	Result
=	Equal	$x = $y	Value of $y is set to variable $x.
+ =	Addition ($x + = $y)	$x = $x + $y	Addition of $x and $y and result store to $x.
- =	Subtraction ($x - = $y)	$x = $x - $y	Subtraction of $x and $y and result store to $x.
* =	Multiplication ($x * = $y)	$x = $x * $y	Multiplication of $x and $y and result store to $x.
/ =	Division ($x / = $y)	$x = $x / $y	Division of $x and $y and result store to $x.
%	Modulus ($x % = $y)	$x = $x % $y	Remainder of $x and $y and result store to $x.

Example:-

<?php
$x = 20;  
$x += 100;

echo $x;
?> 

Output: 120

PHP Comparison Operator: -

PHP Comparison operator are used to compare two values (value would be either number or string).

Opertaor	Name	Example	Operation
= =	Equal	$x = = $y	Check the value of $x is equal to $y or not.
= = =	Identical	$x = = = $y	Check the value of $x is equal to $y and of same data-types(string, int char, etc..).
! =	Not Equal	$x ! = $y	Returns true if $x is not equal to $y.
< >	Not Equal	$x < > $y	Returns true if $x is not equal to $y.
! = =	Not Identical	$x ! = = $y	Check the value of $x is not equal to $y or they are not of  the same data-types(string, int char, etc..).
>	Greater than	$x > $y	Returns true if $x is greater than $y.
<	Less than	$x <  $y	Returns true if $x is less than $y.
> =	Greater than or Equal to	$x > = $y	Returns true if $x is either greater than or equal to $y.
< =	Less than or Equal to	$x < = $y	Returns true if $x is either less than or equal to $y.

One of the most important operator in php is 'SCOPE RESOLUTION OPERATOR(::)' 
Define :-  Scope Resolution Operator or double Colon is a Token that allows access to Static, Contant, Overridden property or method of a class.

Ex 1:  :: from outside the class {DefineClass.php}

<?php
class dog
{
const color = 'My dog is of white color{form DefineClass.php}';
}
echo dog::color;
?>

OUTPUT :-My dog is of white color

Ex 1:  :: from inside the class   {AccessDefineClassMember.php}

<?php include'DefineClass.php' ?>
<?php
class snake extends dog
{
    public static $length='snake is longer than my dog';
    public static function doublecolon() {
        echo parent::color.'<br>';
        echo self::$length.'<br/>';
    }
}
//$classname = 'snake';
//$classname::doublecolon(); // for PHP5.3
snake::doublecolon();
?>

OUTPUT :-   My dog is of white color{form DefineClass.php}
                      snake is longer than my dog

Three special keywords self, parent and static are used to access properties or methods from inside the class definition.