how to get the ipaddress of customer

how to get the ipaddress of customer
<?php	ist connect to database, using require
require 'lesson44.php';	write query to insert + execute+
$user_ip = $_SERVER ['REMOTE_ADDR'];	get the ipaddress of customer and stores into userip variable
//ipaddress of this server
function add_ip ($ip){	write the function to update into database
global $mycon;	we cant use directly global variable for that purpose use global
// if we want to use outside variable in function
$query = "INSERT INTO `hits_ipaddress` (`id`, `ip`) VALUES(NULL, '$ip')";	it is updat into data base, update into database ussing id, hits with no value and ipadress of customer
// write a statement or query to insert into  table
mysqli_query($mycon, $query);	runs this query against database
//run this query on this database
}
?>
how to use the template values and data	require
how to get the ipaddress of custoemr	$_SERVER ['REMOTE_ADDR']
how to write afunction to add ipaddress	function
how to write a function to use global variable	global
how towrite a query to update to database	query
	INSERT INTO VALUE
how to execute a query	mysqli_query