[Oberon] Modulus on negative number

Jörg joerg.straube at iaeth.ch
Wed May 17 08:09:09 CEST 2017


> Am 17.05.2017 um 02:11 schrieb Skulski, Wojciech <skulski at pas.rochester.edu>:
>> x DIV 0 is undefined. 
> I thought than every programming language will rise a trap on division by 0, either integer or floating point. I would be surprised if Oberon did not.

Yes, it does. This is the way to flag „undefined" :-)

> The following two questions are somewhat related to this discussion.
> 1. Does Oberon support NaN? If not then maybe it should?
> 2. Could the "undefined" become "defined as NaN" in all numerical cases which are now undefined? 

„NaN“ is a special value for floating point numbers defined in IEEE 754. In Oberon, DIV and MOD are defined on positive INTEGERs. Hence, no "NaN".


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