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PHP Reference



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Reference in PHP allows two different PHP variables to write to the same value, for example

$reference_var1 = &$reference_var2;

Here both the variable, that is, $reference_var1 and $reference_var2 are equal.

You can say, both variable point to the same place.

PHP Reference Example

Let's take an example that demonstrates reference in PHP.

<html>
<head>
	<title>PHP Reference Example</title>
</head>
<body>
<?php
	$num1 = 10;
	$num2 = &$num1;
	$sum = $num1 + $num2;
	echo $sum;
?>
</body>
</html>

Below is the sample output produced by the above reference example code in PHP.

php reference

Main Use of Reference in PHP

If you assign the reference of any variable say $first_ref_var to a another variable say $second_ref_var, then if you change the value of variable $first_ref_var, the $second_ref_var's value will also be changed automatically, as you have assigned the reference of that variable.

Let's take another example to understand about the main use of reference in PHP.

<html>
<head>
	<title>Reference example in PHP</title>
</head>
<body>
<?php
	echo "With Reference:<br/>";
	// initialize first variable with value
	$num1 = 10;
	// initialize the reference of first variable to second variable
	$num2 = &$num1;
	$sum = $num1 + $num2;
	echo $sum;
	echo "<br/>";
	// change the value of first variable
	$num1 = 20;
	echo $num1;
	echo "<br/>";
	// you will see, the value of second variable will also be changed
	// this is the benefit of using reference in PHP
	echo $num2;
	echo "<hr/>";
	
	echo "Without Reference:<br/>";
	$var1 = 10;
	$var2 = $var1;
	$add = $var1 + $var2;
	echo $add;
	$var1 = 20;
	echo "<br/>";
	echo $var1;
	echo "<br/>";
	echo $var2;
?>
</body>
</html>

Here is the sample output of the above reference example in PHP.

reference in php

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