PHP function ()

[samy]

Hi,

I am relativelly new to PHP programming and have searched a number of newsgroups on the following question:

Can someone explain to me the general difference between, e.g. function xyz () and function xyz ($123, $567)?
Some functions obviously need variables within the parenthesize and some don't. So, were's the difference and how do they function?

I appreciate your help.
Samy

[Wbmstr84]

Both functions have the same name obviously. The first has no parameters(variables sent to it). To call the first one you just need xyz(), to call the second one you need xyz($var1, $var2). Then inside the second function you have access to these two sent variables.

function xyz () 
{
return 1000; // you do the stuff inside and return some value if needed.
}
function xyz ($123, $567)
{
return $123+$567; // you generally manipulate the variables sent and return some value if needed.
} 

Not sure what you are really looking for here?

[AWilliams]

Generally speaking a function with no parameters will return the same thing each time. Accepting parameters like in the second example allows you to change the data somehow.

phpinfo() would be a good example of the first - the output never really changes. in_array() would be a good example of the second type, where you pass arguments to the function, and the function return a value which will vary depending on the arguments.

[samy]

Thanx so far. I think I got the overall idea of how they work, now.

Regards,
Samy

[Floezen]

What is the difference between writing

function xyz ($123, $567)

and

function xyz ()
globals $123, $567;

?

Flözen

[lilleman]

If you use the first method (sending variables as arguments) then you can manipulate them and they will only change inside the function. You can also send any variable you want to the function which makes it easier to reuse. If you declare a variable as global you will always have to name your variable the same.

When you send a variable/value as an argument, you can use a different variable to fetch the returned value.

<?php

function foo($bar)
{
  return $bar . 'Hello World';
}

$bar = 'Just testing...';
echo foo($bar); // prints "Just testing...Hello World"

$foobar = 'Hi World';
$foo = foo($foobar);

echo $foobar; // prints "Hi World"
echo $foo; // prints "Hi WorldHello World"

?>

<?php

function foo()
{
  global $bar;
  $bar .= 'Hello World';
}

$bar = 'Hi World';
$foobar = foo();

echo $bar; // prints "Hi WorldHello World"
echo $foobar; // since foo() doesn't return anything, this variable will be empty

?>

Another thing; the arguments does not have to be variables!

<?php

function foo($value)
{
  return "Your value: $value";
}

echo foo('A little test'); // prints "Your value: A little test"
echo foo(1); // prints "Your value: 1"

?>