Best search algorithm to find condition within a range

Alain Ketterlin alain at dpt-info.u-strasbg.fr
Thu Apr 9 14:56:04 CEST 2015


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

-- Alain.



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