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Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today. # Can't understand how this loop works, do you?

Hi! My name is Emil Wallgren. I'm currently doing a Quiz on Build a simple php application > working with functions > working with functions. I've seen the videos but I don't understand why the solution to this question is as it is. The question is like this:

What does the following code display:

```<?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;

?>
```

I understand it like this:

\$total = 4 since it counts the amount of variables in the array. \$i is also 4 since it adds the number 1 everytime it loops (which is 4 times).

Then the if-statement cant execute since 4 aint less than 4.

We echo \$sum which hasn't changed...so we should get 0...right?

Still when i try the code on my computer...i get 6.

Why?

6 is correct. Go through number by number

First, number = 1. i = 1, sum = 0+1 = 1
number = 2, i=2, sum = 1+2 = 3
number = 3, i=3, sum = 3+3 = 6
number = 4, i=4, sum is not executed.

There ya go, echo sum=6.

I think the only error in your understanding is that \$i doesn't become 4 right away. You seem to realize that the loop will execute 4 times. This means the code inside the loop will execute 4 times. Each time through the loop only 1 is being added to \$i so it doesn't become 4 until the very last time through the loop. Which means the if block is executed the first 3 times through the loop but not the 4th time as you correctly pointed out. Thanks Jason :-)

So the if-statement executes each time the \$i is below 4. Now I get it! You helped me alot there :-)

Thanks again :-D

/E

You are correct that, when i = 4, the if statement is false, thus sum is not executed. Since this is a loop, the code is executed as many times as the loop is iterated. In this case, 4 times.

First time through, i =1, the if statement is processed true. Second time through, i=2...etc

Try adding this right before the if statement:

```echo \$i < \$total;
```