The requirement for a final ``++case default++`` clause is defensive programming. The clause should either take appropriate action, or contain a suitable comment as to why no action is taken. Even when the ``++switch++`` covers all current values of an ``++enum++``, a default case should still be used because there is no guarantee that the ``++enum++`` won't be extended.

== Noncompliant Code Example

----
switch ($param) {  //missing default clause
  case 0:
    do_something();
    break;
  case 1:
    do_something_else();
    break;
}
----

== Compliant Solution

----
switch ($param) {
  case 0:
    do_something();
    break;
  case 1:
    do_something_else();
    break;
  default:
    error();
    break;
}
----

include::../see.adoc[]