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###### Stephen Printup

**UX Design**Techdegree Student 45,252 Points

# Stage 6, Working with functions: Confused

Hi,

I've passed the quiz, but I'm not sure how this works. Could someone please explain it to me?

```
<?php
$numbers = array(1,2,3,4);
$total = count($numbers);
$sum = 0;
$output = "";
$i = 0;
foreach($numbers as $number) {
$i = $i + 1;
if ($i < $total) {
$sum = $sum + $number;
}
}
echo $sum;
?>
```

The options are: A-1234 B-4321 C-321 D-6

## 2 Answers

###### Robert Richey

Courses Plus Student 16,352 PointsHi Stephen,

The easiest way to work through these types of problems is with a sheet of paper, or text editor, to keep track of the values of variables through each iteration of the loop.

The short answer is that `i`

gets incremented before it's checked against the length of the array. So, by the start of the 4th iteration of the loop, `i == 4`

and the if statement evaluates to false. Therefore, the only numbers that got added from the array are 1, 2, and 3.

Hope this helps!

###### Robert Richey

Courses Plus Student 16,352 PointsThink of `$total`

as just the number 4, and `i`

starts at 0.

```
Loop iteration 1:
i += 1
i == 1
i < 4 // True
add current number (1) to sum (0)
sum == 1
Loop iteration 2:
i += 1
i == 2
i < 4 // True
add current number (2) to sum (1)
sum == 3
Loop iteration 3:
i += 1
i == 3
i < 4 // True
add current number (3) to sum (3)
sum == 6
Loop iteration 4:
i += 1
i == 4
i < 4 // False
// sum remains at 6
```

###### Stephen Printup

**UX Design**Techdegree Student 45,252 Points

Thank you, that explains a lot. I thought it was something like that, but the way you explained it helped.

## Robert Richey

Courses Plus Student 16,352 Points## Robert Richey

Courses Plus Student 16,352 PointsHi Stephen,

Fixed markdown to show syntax highlighting. While you had the triple backticks, it was missing the php language specifier.