phpfiddle/fiddle_081354.php

## fiddle_081354.php
<?php
// Start the session
session_start();
?>
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width">
    <link href='http://fonts.googleapis.com/css?family=Ubuntu:400,400italic,700,700italic' rel='stylesheet' type='text/css'>
    <title></title>
    <link rel="stylesheet" type="text/css" href="style.css">
  </head>
  <body>
    <form action="index.php" method="post">
    <div>
      <fieldset>
        <legend id="legend">Add an Employee</legend>
        <label>First Name</label><br>
        <input type="text" name="first" required><br>
        <label>Last Name</label><br>
        <input type="text" name="last" required><br>
        <label>Department</label><br>
        <select name="department">
          <option value="Engineering">Engineering</option>
          <option value="Business">Business</option>
          <option value="Humanity">Humanity</option>
          <option value="Art">Art</option>
          <option value="Natural Science">Natural Science</option>
        </select>
        <br><br>
        <input type="submit">
      </fieldset>
    </div>
    </form>
    <div class="output">
      <?php

        // make an global array that store employee objects
        if (!isset($_SESSION["employees"])) {
          $_SESSION["employees"] = array();
        }
        // make an global array that store 8 digit ids for making sure it is unique
        if (!isset($_SESSION["ids"])) {
          $_SESSION["ids"] = array();
        }
        // make an global array that store firstnames
        if (!isset($_SESSION["firstnames"])) {
          $_SESSION["firstnames"] = array();
        }
        // make an global array that store lastnames
        if (!isset($_SESSION["lastnames"])) {
          $_SESSION["lastnames"] = array();
        }

        // employee class
        class Employee {

          // attr
          public $id;
          public $firstname;
          public $lastname;
          public $department;

          // constructor
          public function __construct($id, $firstname, $lastname, $department) {
              $this->id = $id;
              $this->firstname = $firstname;
              $this->lastname = $lastname;
              $this->department = $department;
          }
        }

        if ($_SERVER["REQUEST_METHOD"] == "POST") {

          // check input value exist
          if(isset($_POST["first"]) && isset($_POST["last"]) && isset($_POST["department"])) {
            // get name, department
            $first_name = $_POST["first"];
            $last_name = $_POST["last"];
            $department = $_POST["department"];

            // if the employee is not exist in employees array, let's add it
            if(!in_array($first_name, $_SESSION["firstnames"] ) && !in_array($last_name, $_SESSION["lastnames"])) {

              // generate random 8 digit number
              $id = rand8();
              // check if this $id is not exist
              while(in_array($id, $_SESSION["ids"])) {
                // generate random integer value again
                $id = rand8();
              }

              // add id to id array
              array_push($_SESSION["ids"], $id);
              // add first name to first names array
              array_push($_SESSION["firstnames"], $first_name);
              // add first name to first names array
              array_push($_SESSION["lastnames"], $last_name);
              // add new employee as json object to employees array
              array_push($_SESSION["employees"], json_encode(new Employee($id, $first_name, $last_name, $department)));

              // output when employee added
              echo "<h3>Employee Added</h3>";
              echo "<p>Name: " . $first_name . ", " . $last_name . "<br>";
              echo "Department: " . $department . "<br>";
              echo "Employee ID: " . $id . "<br>";
              echo "Hire Date: " . date("l m d Y") . "<br>";
              echo "Total Employees: " . count($_SESSION["employees"]) . "<br></p>";

            }

          }

        }// end of post handle

        // 8 digit random number generator
        function rand8() {

          $random_number='';
          $count = 0;

          while ( $count < 8 ) {
            $random_digit = mt_rand(0, 9);
            $random_number .= $random_digit;
            $count++;
          }

          return $random_number;
        }
       ?>
    </div>
    <?php
    // to debug, lets print employees array on browser console in json format
    console_log($_SESSION["employees"]);
    // function to debug
    function console_log($data){
      echo '<script>';
      echo 'console.log('. json_encode( $data ) .')';
      echo '</script>';
    }
    ?>
  </body>
</html>
	<?php
	// Start the session
	session_start();
	?>
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width">
	<link href='http://fonts.googleapis.com/css?family=Ubuntu:400,400italic,700,700italic' rel='stylesheet' type='text/css'>
	<title></title>
	<link rel="stylesheet" type="text/css" href="style.css">
	</head>
	<body>
	<form action="index.php" method="post">
	<div>
	<fieldset>
	<legend id="legend">Add an Employee</legend>
	<label>First Name</label><br>
	<input type="text" name="first" required><br>
	<label>Last Name</label><br>
	<input type="text" name="last" required><br>
	<label>Department</label><br>
	<select name="department">
	<option value="Engineering">Engineering</option>
	<option value="Business">Business</option>
	<option value="Humanity">Humanity</option>
	<option value="Art">Art</option>
	<option value="Natural Science">Natural Science</option>
	</select>
	<br><br>
	<input type="submit">
	</fieldset>
	</div>
	</form>
	<div class="output">
	<?php

	// make an global array that store employee objects
	if (!isset($_SESSION["employees"])) {
	$_SESSION["employees"] = array();
	}
	// make an global array that store 8 digit ids for making sure it is unique
	if (!isset($_SESSION["ids"])) {
	$_SESSION["ids"] = array();
	}
	// make an global array that store firstnames
	if (!isset($_SESSION["firstnames"])) {
	$_SESSION["firstnames"] = array();
	}
	// make an global array that store lastnames
	if (!isset($_SESSION["lastnames"])) {
	$_SESSION["lastnames"] = array();
	}

	// employee class
	class Employee {

	// attr
	public $id;
	public $firstname;
	public $lastname;
	public $department;

	// constructor
	public function __construct($id, $firstname, $lastname, $department) {
	$this->id = $id;
	$this->firstname = $firstname;
	$this->lastname = $lastname;
	$this->department = $department;
	}
	}

	if ($_SERVER["REQUEST_METHOD"] == "POST") {

	// check input value exist
	if(isset($_POST["first"]) && isset($_POST["last"]) && isset($_POST["department"])) {
	// get name, department
	$first_name = $_POST["first"];
	$last_name = $_POST["last"];
	$department = $_POST["department"];

	// if the employee is not exist in employees array, let's add it
	if(!in_array($first_name, $_SESSION["firstnames"] ) && !in_array($last_name, $_SESSION["lastnames"])) {

	// generate random 8 digit number
	$id = rand8();
	// check if this $id is not exist
	while(in_array($id, $_SESSION["ids"])) {
	// generate random integer value again
	$id = rand8();
	}

	// add id to id array
	array_push($_SESSION["ids"], $id);
	// add first name to first names array
	array_push($_SESSION["firstnames"], $first_name);
	// add first name to first names array
	array_push($_SESSION["lastnames"], $last_name);
	// add new employee as json object to employees array
	array_push($_SESSION["employees"], json_encode(new Employee($id, $first_name, $last_name, $department)));

	// output when employee added
	echo "<h3>Employee Added</h3>";
	echo "<p>Name: " . $first_name . ", " . $last_name . "<br>";
	echo "Department: " . $department . "<br>";
	echo "Employee ID: " . $id . "<br>";
	echo "Hire Date: " . date("l m d Y") . "<br>";
	echo "Total Employees: " . count($_SESSION["employees"]) . "<br></p>";

	}

	}

	}// end of post handle

	// 8 digit random number generator
	function rand8() {

	$random_number='';
	$count = 0;

	while ( $count < 8 ) {
	$random_digit = mt_rand(0, 9);
	$random_number .= $random_digit;
	$count++;
	}

	return $random_number;
	}
	?>
	</div>
	<?php
	// to debug, lets print employees array on browser console in json format
	console_log($_SESSION["employees"]);
	// function to debug
	function console_log($data){
	echo '<script>';
	echo 'console.log('. json_encode( $data ) .')';
	echo '</script>';
	}
	?>
	</body>
	</html>