Return in a loop

Question

Can someone tell me why the result bellow should be 10 and not 0, 1, 2, 3, 4. Thanks. My process is. I take 5, plug it in the loop and get 0, 1, 2, 3, 4. Then I add 0 to these results which still gives me 0, 1, 2, 3, 4.

function func($arg) {
$result = 0;
for($i=0; $i<$arg; $i++) {
$result = $result + $i;
}
return $result;
}
echo func(5);

Answer 1

$result = $result + Si;

0 + 1, $result becomes 1
1 + 2, $result becomes 3
3 + 3, $result becomes 6
6 + 4, $result becomes 10.

Function returns value after loop has ended, and returns 10.

Answer 2

Ok, that explains why the $result = 0 is written outside the loop. I didn't understand that. Thanks.

Answer 3

@Alexis

Yes, you want to ensure you're not resetting to zero, and: $result is there is because you can't add to $result without defining it first.

Remove the initializer (regardless of its value) and this happens:

Notice: Undefined variable: result

because:

$result = undefined_variable + $i;

Answer 4

Function returns value after loop has ended, and returns 10.