[ProgSoc] Randomisation

[Jay Banyer <jay@nospam.vma.tabnsw.com.au>]

Chaos gurus (oxymoron?),

I have a number of entities (c structures actually), and I have to
randomly re-arrange their order. The randomisation should be without
bias.

The method I am using is taken from the book 'C: how to program' (PP
text, I forget the authors. Deitel?). I would like your comments on its
integrity, effectiveness and un-biasness. (wince :)

I know how many structures their are. I malloc space for an array of
pointers to these structures. I initialise the array of pointers to
point to the structures in the order that I read them from a file. Using
a for loop, I go through each and every pointer, in order, and swap it
with another pointer chosen randomly from the array (including itself).

I use 

        index = rand() % num_structures;

to pick the random index, and I have seeded the randomiser once before
beginning the process using

        srand(time(NULL));

Any comments appreciated, although please include explainations of your
thoughts.

j.

-- 
Don't stress it - it's only 1s and 0s.
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