PHP repeating piece of code wtih access to variables - php

Question

How to repeat the same PHP snippet in different PHP files?
For example I define the variable $user, then I insert PHP code, which have an access to this variable.
Update:
I'm going to use this with if statement
Example(without if statement):
function sanitizeString($var)
{
$var = htmlentities($var, ENT_QUOTES, "UTF-8");
return mysql_real_escape_string($var);
}
$user = sanitizeString($_POST['user']);
$pass = sanitizeString($_POST['pass']);
//code i want to repeat in different files
$user=$user;
$pass=$pass;
#salt generation
$salt=uniqid(mt_rand(), true);
#Add data to tables
queryMysql("INSERT INTO accounts VALUES('$user', '".hash('sha512',$pass+$salt)."', '$salt', '$cookie_value')");
mysql_query("INSERT INTO passwordreset VALUES('$user', NULL, NULL)");
//end of code to repeat

Answer 1

Use functions with parameters, that's what they're for. Snippets of code that can be reused in a different context with different variables.

Answer 2

Make classes and methods
class User
{
public $user;
public function User($name)
{
$user = $name;
}
}
$User = new User('name1');
echo $User->user;
$User = new User('name2');
echo $User->user;
$User = new User('name3');
echo $User->user;
$User = new User('name4');
echo $User->user;
Output: name1name2name3name4

Answer 3

U Can add the code or variable in one php file and then include that file where ever u want
U can see the example here

Answer 4

(Removed global keyword as it is not necessary in this case)
One method is to use the $GLOBALS variable, which is accessible anywhere much like $_SERVER, $_POST etc. See Superglobals. As Deceze mentioned, global variables are typically not the best solution, as they are prone to causing accidental errors. For more information about this, give this a read.
$GLOBALS['user'] = "RadGH";
include "my_file.php";
my_file.php:
echo $GLOBALS['user'];
From Bondeye in a comment, using a constant is preferred when dealing with data that does not need to be changed. One of the problems with globals is that somewhere down the line data may be changed or referenced accidentally. Since constants cannot be changed, that is not the case.
define('USER', 'RadGH');
include "my_file.php";
my_file.php:
echo USER;