62. Enum Classes

Question.6

A developer receives a byte from UART and casts it to an enum class:

enum class Command : uint8_t { READ=1, WRITE=2, RESET=3 };

uint8_t raw = uart_read();  // Could be any value 0-255
Command cmd = static_cast<Command>(raw);

If raw = 99, what happens?

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Compilation error -- 99 is not a valid Command value
cmd holds the value 99 -- the cast succeeds without validation; enum class does not validate at runtime
cmd is set to the nearest valid value (RESET)
Undefined behavior -- invalid enum values crash

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