PHP call by value

PHP functions can be called in two ways:

Call By Value
Call by Reference

In PHP call function by value, modification of values inside a function does not modify the actual value.
Example 1

<!DOCTYPE html>
<html>
<body>
 
<?php  
function adder($x)  
{  
$x .= 'Call By Value';  
}  
$y = 'Hello PHP';  
adder($y);  
echo $y;  
?> 
 
</body>
</html>

Output

Hello PHP

Example 2

<!DOCTYPE html>
<html>
<body>
 
<?php  
function incre($i)  
{  
$i++;  
}  
$i = 1;  
incre($i);  
echo $i;  
?> 
 
</body>
</html>

Output

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