Why is this an issue?
switch can contain a default clause for various reasons: to handle unexpected values, to show that all the cases were
properly considered.
For readability purpose, to help a developer to quickly find the default behavior of a switch statement, it is recommended to put the
default clause at the end of the switch statement. This rule raises an issue if the default clause is not the
first or the last one of the switch's cases.
Noncompliant code example
switch (param) {
case 0:
doSomething();
break;
default: // default clause should be the first or last one
error();
break;
case 1:
doSomethingElse();
break;
}
Compliant solution
switch (param) {
case 0:
doSomething();
break;
case 1:
doSomethingElse();
break;
default:
error();
break;
}
Resources
- MISRA C:2004, 15.3 - The final clause of a switch statement shall be the default clause
- MISRA C++:2008, 6-4-6 - The final clause of a switch statement shall be the default-clause
- MISRA C:2012, 16.4 - Every switch statement shall have a default label
- MISRA C:2012, 16.5 - A default label shall appear as either the first or the last switch label of a switch statement
