Hi Hiroki, > Is this a bug or am I violating C++ standard? The code violates the C++ standard. The used range of Quartet is -1 ... 2, which can be expressed in 3 signed bits (0b111 is -1, 0b010 is 2), a signed bit-range of -4 (0b100) to 3 (0b011). 42 and 129 do not fit in this range. Casting 42 and 129 into that range is undefined. The C++ compiler *KNOWS* that case FOURTY_TWO cannot be accessed, and is dead code. Why? Because according to ISO 14882, Quartet *MUST* be between -4 and 3 (3 signed bits). And it *KNOWS* that int i was set from a Quartet. The optimization that is performing that behavior is -ftree-dominator-opts, which is enabled by -O1 and higher. If you compile the code as C (via gcc) instead of C++ (via g++), you'll notice that the same -ftree-dominator-opts does not optimize away the FOURTY_TWO. Why? Because in ISO 9899, an enum is held in a signed int or an unsigned int. Also some nits... C++ should use the C++ header file, #include <cstdio>, and not the C header file #include <stdio.h>. And the return type should be char const*, and not char*. And, in my opinion, C++ code should avoid using C-style casts and instead should use C++ verbose casts. HTH, --Eljay
