What is the difference between these 2 codes

Question

// code1

<?php
function mult($num1, $num2) {
$res = $num1 * $num2;
echo $res;
}

mult(8, 3);
?>

// code2

<?php
function mult($num1, $num2) {
$res = $num1 * $num2;
return $res;
}

echo mult(8, 3);
?>

what is the point of "return" ?!

Answer 1

returns gives you the value. The result of the function.

So with the return mult, you can store it in other variable, or even do

$res = mult(mult(2,2),2) so the inside mult will be 4, and because it was returned, the expresion goes to mult(4,2).

so $res is 8.

Answer 2

in code2 the function returns the result to the point of call. so you can print outside the function, or do other things with that result value.