Pass old input/ get old input from view after Form Request validation in laravel

Sometimes we need to get old values in form to show them when error back to the same form, It is now well organized in Laravel. Consider the following situations:

1. Suppose you submitted a form with some values.
2. Found some errors and send back to the form again from Laravel controller to show the form again.
3. You have to show the values when he was here few moments ago (before submit the form)

$username = Request::old('username');

or in view:

{{ old('username') }}