<?php
$first = 100;
$second = 200;
$third = $first + $second;
echo "Sum = ".$third;
// Destroy a variable with unset function
unset($third);
//after delete the variable call it again to test
echo "Sum = ".$third;
?>
<?php
$a = "Hello world!";
echo
"The value of variable 'a' before unset: " . $a . "<br>";
unset($a);
echo
"The value of variable 'a' after unset: " . $a;
?>