Having problems with Code Challenge: Introducing User-Defined Functions

Here's the answer as I would write it:

<?php 

    function mimic_array_sum($array){
        $sum_working = 0;
        foreach($array as $number){
            $sum_working = $sum_working + $number;
        }
        return $sum_working;
    }


    $palindromic_primes = array(11, 757, 16361);
    $sum = mimic_array_sum($palindromic_primes);
    echo $sum;

?>

You want to declare a variable inside the function and set it equal to zero before starting the foreach loop. It doesn't need to be called $sum. Variables inside of a function are not accessible outside of the function, so you can call them whatever you want.

You could get the right output in this example by just echoing out the return value of the function like you did. But most of the time you'll need to do more than just echo out the return value from a function to the screen; you'll usually need to store the return value in a variable so that you can do more with it later in code. I wanted to make sure everyone had a good understanding of how to do that.

Does that help?

Just looking over your code - You are calling the function before it knows that the array exists.

Try moving:

mimic_array_sum($palindromic_primes);

To the bottom.

I just tried that code challenge myself! And it doesnt seem like its working properly!

I tried outputting something at all to the preview screen. That didnt work.

I created the full script on the page, and it didnt output anything in the preview. Pasted it to my localhost: worked flawless!

They might have some issues.

Hey Chris !

thanks for the reply, i did notice i did not place the call to the function after the array. good find! the task 2 seems to work properly for me and im guessing that was probably what i did to get pass the the other couple times.

but now my original problem insists,

task 3; <p>In the main code, outside of the function, use the new mimic_array_sum() function you just wrote. Store the return value in a variable called $sum, and then display that sum to the screen.</p>

my code already has $sum variable, i understand the challenge is asking me to place it outside my function, this is what is essentially missing for me to pass

<?php 


function mimic_array_sum($array){
$sum = 0;
foreach($array as $number){
$sum = $sum + $number;
}
return $sum;    
} 


$palindromic_primes = array(11, 757, 16361);
mimic_array_sum($palindromic_primes);
?>

now do i need to make it: <?php

$sum = 0 //*declare sum*//
function mimic_array_sum($array);
foreach(yadda yadda)
$sum = //* decalre here*//

?>

Hey Chris,

I also noticed that the preview screen does not seem to work properly, which was confusing me to the point i was just using notepad++ to validate the code myself.

but before you had checked it and helped with the flaw i had, the error i was getting simply was that my argument was incorrect.

hope the guys at treehouse fix that little bug. if you have any solutions to my problem for task 3 of the challenge, please feel free to chime in

thanks guys!

try printing the value of $sum in your function instead of returning the value! :)

OR

print out the return value of the function.

As the challenge doesnt work for me, i dont know the specifics of the code challenge.

No that didnt seem to do the trick . the error i seem to keep receiving is that my $sum variable is not showing a value .

at this point the $sum variable is not in the function and is declared outside of the mimi_array_sum( to my knowledge)

when i preview the page it gives the sum of all three numbers : 17129

code i entered for task 3:

<?php 

$sum = 0;
function mimic_array_sum($array){
foreach($array as $number){
$sum = $sum + $number;
}
return $sum;
}


$palindromic_primes = array(11, 757, 16361);

echo mimic_array_sum($palindromic_primes);

?>

i have been stuck on this too long. any help would be great.

any teamtreehouse help would also be great !

thanks,

-justin

Hey Justin,

This last code snippet is almost there. Your mimic_array_sum() looks good, though I'd recommend having $sum = 0 inside the function to start.

Here are the instructions for the last step:

In the main code, outside of the function, use the new mimic_array_sum() function you just wrote. Store the return value in a variable called $sum, and then display that sum to the screen.

This one line ...

echo mimic_array_sum($palindromic_primes);

... should first store the return value in a variable, like this ...

$sum = mimic_array_sum($palindromic_primes);
echo $sum;

Does that make sense?

yea that makes sense as to what your doing, but in regards to why your doing it i am confused Randy, why do i need to declare $sum =mimic_array_sum($palindromic_primes) outside of the function, when the function itself is returning the $sum of the of the array in with the loop? i am also still confused as to the placement of the declared value of $sum = mimic_array_sum($palindromic_primes) does this variable get placed after the function between the two curly brackets ? or im assuming its before you print out the command and list it next to the $palindromic_prime variable.

thanks for the help randy!

i look forward to your response asap.

-justin

Gotcha !

yes that makes much more sense. I guess the fact that i was just declaring the same name for the variable was confusing me, but as you stated the name makes no difference due to the function only being able to see the variable.

thank you sir!

-justin