Creating Variable Within Function. Using it Outside of Function.

[DamienRoche]

So I thought I'd get to using php in a more OO way. Created my first function and read up on variable scope. What I couldn't find the answer to was how to use a variable if it was created within a function..or even if this is possible.

 

So here's a basic function to illustrate this:

 

function addthis(){

$num1 = 2; $num2 = 3;

$total = $num1 + $num2;

return $total;
}

addthis();

echo "$total";

 

This doesn't output anything and no doubt has something to do with variable scope. But I can't get my head around it. How do I define a variable in a function and then use it outside that function?

 

I've tried the global thing in a few places, but still nothing.

 

 

Hopefully someone can shed some light on this. Thanks.

[discomatt]

This isn't OO(P). Functions != Objects.

 

Read up here:

http://php.net/manual/en/language.oop5.basic.php

 

But here's your solution

 

function addthis(){

$num1 = 2; $num2 = 3;

$total = $num1 + $num2;

return $total;
}

$total = addthis();

echo "$total";

 

Variables inside of functions are completely separate from variables outside, and vice versa. You can change this by using the global keyword, but it's not considered good coding practise

[DamienRoche]

Thanks for clearing up my OO misconception.

 

Onto to the problem. I know I can turn that functions output into a variable. but what if I have several variables I want to use within that function.

 

Am I trying to do something I should be classes or objects?

 

Basically, I have some code at the beginning of a few pages, very specific to that page..they simply define a few variables that are used throughout the page. What I want to know now is how can put these snippets of code into a *master file* and simply include the file in each page and refer to a snippet of code.

 

I'm trying to enclose these snippets with something.

 

I was trying to use functions...but obviously that won't work. Can I use classes to do this?

 

Thanks again for the help.

[discomatt]

Couple ways to do this... pass by reference, and using a class (OOP)

 

<pre><?php

function byReference( $int, & $total ) {
$total = $int + 5;
}

$globalTotal = 12;
echo "\$globalTotal = $globalTotal before byReference()\n";

byReference( 10, $globalTotal );
echo "\$globalTotal = $globalTotal after byReference()\n";

class someClass {

public $total = 12;

public function add5 ( $int ) {
	$this->total = $int + 5;
}

}

$obj = new someClass;

echo "\$obj->total = {$obj->total} before add5()\n";

$obj->add5( 10 );
echo "\$obj->total = {$obj->total} after add5()\n";

?></pre>

[jonsjava]

rather than using a class. Here's a *slight* mod on your script:

<?php
function addthis(){
$num1 = 2;
$num2 = 3;
$total = $num1 + $num2;
return $total;
}
$total = addthis();
echo $total;

You'll never see me OOP.  I'm a procedural guy. I can think in procedural. Never could OOP think.

[jonsjava]

oh, and to handle an array output from a function, here's another version of the same thing:

<?php
function addthis(){
$count = 5;
while ($count > 1){
	$number1 = rand(1,100);
	$number2 = rand(1000,2000);
	$finals[] = $number1 + $number2;
	$count--;
}
return $finals;
}
$total = addthis();
print_r($total);

[discomatt]

But objects are the way of the awesome....

 

And yes, returning an array would be 'better' than passing by reference ( in a scope sense anyways )...

[jonsjava]

a well-written object will run much faster than a function that does the same thing. With that said, you gotta decide if you need the speed. If it's a simple function to do something like I wrote, then you prolly don't need the time difference.  I know how to OOP, but I hate doing it.  It doesn't come to me as rapidly as procedural code.