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.
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.
PHP Online Test
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