Interpreting "Running Membership with Sessions"

Original - php Code <?php // functions.php function secure () { if (!($_SESSION["member_id"]) || ($_SESSION["member_id"] == "")) { Header("Location: ./login.php"); exit(); } } function login_check ($forms) { $error = ""; $username = $forms["username"]; $password = $forms["password"]; if (trim($username) == "") $error .= "<li>Your username is empty.</li>"; if (trim($password) == "") $error .= "<li>Your password is empty.</li>"; /* from here, do your sql query to query the database to search for existing record with correct username and password */ if (trim($error)!="") return $error; } function login ($forms) { $username = $forms["username"]; $password = $forms["password"]; /* do your sql query again, but now returning the id of member */ return $member_id; } ?>

<?php
// functions.php
 
function secure () {
  if (!($_SESSION["member_id"]) || ($_SESSION["member_id"] == "")) {
    Header("Location: ./login.php");
    exit();
  }
}
function login_check ($forms) {
  $error = "";
  $username = $forms["username"];
  $password = $forms["password"];
  if (trim($username) == "") $error .= "<li>Your username is empty.</li>";
  if (trim($password) == "") $error .= "<li>Your password is empty.</li>";
  /* from here, do your sql query to query the database to search for existing record with correct username and password */
  if (trim($error)!="") return $error;
}
 
function login ($forms) {
  $username = $forms["username"];
  $password = $forms["password"];
  /* do your sql query again, but now returning the id of member */
  return $member_id;
}
?>  

Original - php Code <?php // login.php session_start(); include ("functions.php"); if ($_POST) { $error = login_check($_POST); if (trim($error)=="") { $_SESSION["member_id"] = login($_POST); Header("Location: ./index.php") // Redirect correct member exit(); } else { print "Error:$error"; } } ?> <form method="post"> Username : <input type="text" name="username"><br /> Password : <input type="password" name="password"><br /> <input type="submit" value="Login"> </form>

<?php
// login.php
session_start();
include ("functions.php");
if ($_POST) {
  $error = login_check($_POST);
  if (trim($error)=="") {
    $_SESSION["member_id"] = login($_POST);
    Header("Location: ./index.php") // Redirect correct member
    exit();
  } else {
    print "Error:$error";
  }
}
?>
<form method="post">
Username : <input type="text" name="username"><br />
Password : <input type="password" name="password"><br />
<input type="submit" value="Login">
</form> 

Original - php Code <?php // index.php include("functions.php"); session_start(); secure(); ?>

<?php
  // index.php
  include("functions.php");
  session_start();
  secure();
?>