Mail Archives: djgpp/1998/03/23/11:51:25
G DOT DegliEsposti AT ads DOT it wrote:
>
> >If anyone could tell me how to get REAL random generated numbers under
> >djgpp ... and/or explain me how it works ! I wonder for a long time how
> >a computer can generate random numbers
>
> I would like to know it too! ;-)
>
> Computers cannot generate real random numbers, what they can do is run some
> program in a deterministic way. (at least PCs do :-)
Hmmm... That isn't true, you can easilly create a random number generator using
a diode and an A/D, or just sampling the enviroment sound ;-). There are a lot
of cases like that, not all involves an A/D converter, some signals (not
properlly grounded, etc) have random patterns. You can do it, but you need some
hard.
> Random numbers on PCs are actually pseudo-random numbers. They are
> generated
> using some functions with particular mathematical properties:
> they return numbers very well distributed on a particular set of values and
> IIRC they return the original sequence of values only after a number of
> calls
> greater then the cardinality of the given set of values.
>
> This makes the functions look like if they generate random numbers, but
> they actually don't!
And that's a feature because in this way you can test programs with random
values more than ones and with the same values, or use an encripting methode
using "random" numbers.
SET
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