title: Multiple if-else conditions in ios
body: <p>I have a sign-up view controller that contains multiple text fields to register the user.
  I need to validate all the text fields such as <strong>not empty</strong>, <strong>valid email</strong>, <strong>username</strong>, <strong>password</strong> etc. and display the alert message for all different condition.</p>
  
  <p>Now I following the approach as:</p>
  
  <pre><code>if (condition) {
      if (condition) {
          if (condition) {
          } else {
              [alert show];
          }
      } else {
          [alert show];
      }
  } else {
      [alert show];
  }
  </code></pre>
  
  <p>I know this is not the best approach. So guys please suggest an appropriate way to do that task.</p>
  
  <p>Thanks,</p>