Returning a reference from a function allows you to directly operate on the return value and have those changes directly reflected in the original variable.
When returning a reference from a function, you must return a reference to a variable, not a string.
To return a reference from a function, you use the return statement, but you use & in front of its name when creating it. You also use & when getting the return value from a function that returns a reference.
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<title>PHP</title>
<meta Name="Author" Content="Hann So">
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<?php
// Place an & before the name of the function
// if you want to return a value by reference.
function &Add(&$num1, $num2 = "3")
{
return $num1+$num2;
}
// Set a value to a variable
$val = 2;
// You must use =& assignment operator to invoke the function.
// You pass the variable $val by reference for the first argument.
$sum =& Add($val);
echo "The sum is returned by reference: ", $sum, "<br />";
// Just take the value and not the reference
$sum = Add($val);
echo "The sum is returned by value: ", $sum, "<br />";
// The arguments are just passing by values
function &display_bold($string, $tag = 'b')
{
return "<$tag>$string</$tag>";
}
$string="Hello World";
$ref =& display_bold($string);
echo "The string is returned by reference: ", $ref, "<br />";
// Take the value
$ref = display_bold($string, 'i');
echo "The string is returned by value: ", $ref, "<br />";
?>
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