When the execution is not explicitly terminated at the end of a switch case, it continues to execute the statements of the following case. While this is sometimes intentional, it often is a mistake which leads to unexpected behavior.

## Noncompliant Code Example

    switch (myVariable) {
      case 1:
        foo();
        break;
      case 2:  // Both 'doSomething()' and 'doSomethingElse()' will be executed. Is it on purpose ?
        doSomething();
      default:
        doSomethingElse();
        break;
    }

## Compliant Solution

    switch (myVariable) {
      case 1:
        foo();
        break;
      case 2:
        doSomething();
        break;
      default:
        doSomethingElse();
        break;
    }

## Exceptions

This rule is relaxed in the following cases:

    switch (myVariable) {
      case 0:                                // Empty case used to specify the same behavior for a group of cases.
      case 1:
        doSomething();
        break;
      case 2:                                // Use of return statement
        return;
      case 3:                                // Use of throw statement
        throw new IllegalStateException();
      case 4:                                // Use of continue statement
        continue;
      default:                               // For the last case, use of break statement is optional
        doSomethingElse();
    }

## See

- MISRA C:2004, 15.0 - The MISRA C switch syntax shall be used.
- MISRA C:2004, 15.2 - An unconditional break statement shall terminate every non-empty switch clause
- MISRA C++:2008, 6-4-3 - A switch statement shall be a well-formed switch statement.
- MISRA C++:2008, 6-4-5 - An unconditional throw or break statement shall terminate every non-empty switch-clause
- MISRA C:2012, 16.1 - All switch statements shall be well-formed
- MISRA C:2012, 16.3 - An unconditional break statement shall terminate every switch-clause
- MITRE, CWE-484 - Omitted Break Statement in Switch
- CERT, MSC17-C - Finish every set of statements associated with a case label with a break statement
- CERT, MSC18-CPP - Finish every set of statements associated with a case label with a break statement