[RESOLVED] Fatal error when calling a nested function

[skiabox]

Here's the list :

<?php
function salestax($price,$tax) {
function convert_pound($dollars, $conversion=1.6) {
return $dollars $conversion;
}
$total = $price + ($price $tax);
echo "Total cost in dollars: $total. Cost in British pounds: "
.convert_pound($total);
}
echo convert_pound(15);
?>

I get this error :

Fatal error: Call to undefined function convert_pound() on line 18

line 18 is this : echo convert_pound(15);

[laserlight]

Define the two functions separately:

<?php
function convert_pound($dollars, $conversion = 1.6) {
    return $dollars * $conversion;
}

function salestax($price, $tax) {
    $total = $price + ($price * $tax);
    echo 'Total cost in dollars: ' . $total
         . '. Cost in British pounds: ' . convert_pound($total);
}

echo convert_pound(15);
?>

[skiabox]

Basically I am reading a book and it says that u can call a nested function.Is it true?

[NogDog]

The inner function is not defined until the containing function has been called. Therefore you would have to call the salestax() function at least once before you can call the convert_pound() function by itself.

PS: While you can have function definitions within function definitions, it can be confusing and is the sort of thing I would try to avoid in order to make it easier to maintain my code and my sanity.

[skiabox]

I copy the entire code block from the book :

<?php
function salestax($price,$tax) {
function convert_pound($dollars, $conversion=1.6) {
return $dollars $conversion;
}
$total = $price + ($price $tax);
echo "Total cost in dollars: $total. Cost in British pounds: "
.convert_pound($total);
}
salestax(15.00,.075);
echo convert_pound(15);
?>

This code when executed displays only the outcome of the 1st command (salestax).I get no results from the 2nd command (echo convert.....).

[laserlight]

It works for me. What is your output? I get:

Total cost in dollars: 16.125. Cost in British pounds: 25.824

EDIT:
By the way, if the output looks like the "echo convert_pound(15)" did not work, consider that 15 * 1.6 = 24... so the 24 is being printed, but due to poor formatting it looks like part of the previous output.

[NogDog]

What LL said, put a <br> or something between the two function calls so that their outputs are on separate lines.

[skiabox]

Oh.What an oversight from my side!Sorry guys!I am feeling so ashamed.Thnx anyway for the rapid answers.You have a great forum here!

[NogDog]

skiabox wrote:

Oh.What an oversight from my side!Sorry guys!I am feeling so ashamed.Thnx anyway for the rapid answers.You have a great forum here!

No problem. As you become more experienced with PHP, you'll just find different and more creative ways to make silly mistakes. 🙂

If your question is fully resolved now, you can click the "Thread Tools" link at the top of this thread and then select the "Mark Thread Resolved" option.

[Weedpacket]

NogDog wrote:

The inner function is not defined until the containing function has been called. Therefore you would have to call the salestax() function at least once before you can call the convert_pound() function by itself.

And just to complete that. Once you've called the salestax() function, the convert_pound() function has been defined; if you call the salestax() function again, it will attempt to define the convert_pound() function again, and that itself will be a fatal error.

Being able to define functions within other functions does have its uses, but it usually happens a lot more implicitly than that, and it's not something you'd be likely to do Just Because You Can™.

[NogDog]

You could use a conditional definition, if you really feel the need to have the complication of functions defined within functions. 🙂

<?php
header('Content-Type: text/plain');
function test()
{
   if(!function_exists('prt'))
   {
      function prt()
      {
         echo "Hello, World!\n";
      }
   }
   prt();
}
echo "1: ";
test();
echo "2: ";
test();
/*
OUTPUT:

1: Hello, World!
2: Hello, World!

*/

[Weedpacket]

What I'm more likely to do is

function load_stuff()
{
   if(OPERATING_MODE=='sparkly')
    require_once('sparkly_functions.php');
  else
    require_once('plain_functions.php');
}

And the once-and-only-once defining is built into "_once" 🙂