Argument passing for dummies, for somebody else. Gross oversimplifications.

argument-passing-for-dummies.php

<?php

/* Let's say we have this function, it just adds one to a
 * number and returns the resulting value.
 *
 * It takes in a paramater, which we call $number.
 * 
 * $number is a variable which only exists within the function, when we try
 * to access $number from outside the function, it simply doesn't exist. 
 * $number simply refers to whatever we've passed to addOneToNumber. We use
 * it inside addToNumber to refer to what you've passed to it.
 */

function addOneToNumber($number)
{
  $newNumber = $number + 1;
	
	return $newNumber;
}


// we can call it, passing in whatever we want.

// this includes constant values (like numbers).
$var1 = addOneToNumber(22.2); // var1 would equal 23.2

// you can pass in variables.
$pi = 3.14159
$piPlus1 = addOneToNumber($pi); // $piPlus1 would be 4.14159

// you could even pass in the result of another function.
function takeOneFromNumber($number)
{
	$new = $number - 1;
	
	return $new;
}

addOneToNumber(takeOneFromNumber(2));   /* this would equal 2, because we're getting the OUTPUT of
* takeOneFromNumber() (what it returns) and feeding it TO
* addOneToNumber(), for example.
*
* takeOneFromNumber(2) will equal 1.
* addOneToNumber(1) will equal 2.
*
* Since we're taking one from a number, and adding it back
* on again, we're getting the same number (hopefully).
*/