title: Undefined variable error in PHP
body: <pre><code>Notice: Undefined variable: username in C:\xampp\htdocs\test_class.php
          on line 20
  Notice: Undefined variable: password in C:\xampp\htdocs\test_class.php
          on line 20
  </code></pre>
  
  <p>I get the above error when i use this piece of code for checking down my username and password with my database. </p>
  
  <pre><code>&lt;?php
      class test_class {
  
          public function __construct() { 
  
          }
          public function doLogin() {
  
              include("connection.php");
  
              if (isset($_POST['username']))
                  {
                  $username= $_POST['username'];
                  }
                  if (isset($_POST['password']))
                  {
                  $password= $_POST['password'];
                  } 
  
              $query = "SELECT * FROM users WHERE username = '$username' AND password = '$password'";
              $result = mysql_fetch_array(mysql_query($query));
              if(!$result)
  
              {
  
              return 'assa';
  
              }else{
  
              return 'assa112121212';
  
              }
  
                  }
          }
  ?&gt;
  </code></pre>