how to require https in php code example

Example 1: force https with php

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

Example 2: make php website https

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://www.example.com/$1 [R=301,L]