how to get http to redirect to https code example

Example 1: how to redirect http to https

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

Example 2: redirect https

if ($_SERVER['HTTPS'] != "on") 
{
    $url = "https://". $_SERVER['SERVER_NAME'] . $_SERVER['REQUEST_URI'];
    header("Location: $url");
    exit;
}