Best search algorithm to find condition within a range

Marko Rauhamaa marko at pacujo.net
Thu Apr 9 15:28:37 CEST 2015


Alain Ketterlin <alain at dpt-info.u-strasbg.fr>:

> Marko Rauhamaa <marko at pacujo.net> writes:
>
>> Alain Ketterlin <alain at dpt-info.u-strasbg.fr>:
>>
>>> No, it would not work for signed integers (i.e., with lo and hi of
>>> int64_t type), because overflow is undefined behavior for signed.
>>
>> All architectures I've ever had dealings with have used 2's-complement
>> integers. Overflow is well-defined, well-behaved and sign-independent
>> wrt addition, subtraction and multiplication (but not division).
>
> You are confused: 2's complement does not necessarily mean modular
> arithmetic. See, e.g.,
> http://stackoverflow.com/questions/16188263/is-signed-integer-overflow-still-undefined-behavior-in-c

Ah, ok, I misunderstood your point. However, what I meant originally is
that the given uintX_t implementation would work even if it were given
intX_t arguments, and the returned uintX_t can be assigned to an intX_t
variable safely.


Marko



More information about the Python-list mailing list