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In this noncompliant code example, the case where the card is 11 lacks a break statement. As a result, execution continues with the statements for card = 12.
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The break statement at the end of the final case in a switch statement may be omitted. By convention, this is the default label. The break statement serves to transfer control to the end of the switch block. Fall-through behavior also causes control to arrive at the end of the switch block. Consequently, control transfers to the statements following the switch block without regard to the presence or absence of the break statement. Nevertheless, the final case in a switch statement should end with a break statement in accordance with good programming style [Rogue Vermeulen 2000].
Exceptionally, when multiple cases require execution of identical code, then break statements may be omitted from all cases except the last one. Similarly, when processing for one case is a proper prefix of processing for one or more other cases, the break statement may be omitted from the prefix case. This should be clearly indicated with a comment. For example:
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Also, when a case ends with a return or throw statement, the break statement may be omitted.
Bibliography
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