Experiences/guidance on teaching Python as a first programming language
Steven D'Aprano
steve at pearwood.info
Wed Dec 18 02:53:24 EST 2013
On Wed, 18 Dec 2013 01:33:03 +0000, Steven D'Aprano wrote:
>> or just what operation "x + y" is
>> actually going to perform.
>
>
> With no operator overloading, that one at least is correct.
Actually, I stand corrected. I was completely mistaken about that. The C
operation x + y is undefined if the addition overflows. A valid C
compiler can produce whatever code it damn well feels like in the case of
overflow.
Oh, and in case you think that integer overflow in C will always follow
two's complement semantics, such that INT_MAX+1 = INT_MIN, you are wrong.
That's not guaranteed either. Clang and gcc have a flag, -fwrapv, to
force defined behaviour on integer overflow, but that's not part of the C
standard and not all C compilers will do the same.
--
Steven
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