Reply to Sergey,
Mon, 8 Dec 2008 06:59:40 +0000 (UTC), BCS wrote:
better (I think):
rand() / (RAND_MAX / TYPES_OF_TILES)
Don't use rand() like this, ever. ;) "RAND_MAX / TYPES_OF_TILES" is
an integer expression, it rounds down, therefore your formula gives a
slightly greater range of values than you expect. You'll get all
sorts of out of bounds errors.
thus the (I think). I was just to lazy to figure out the rounding.
the idea still work as long as you round up.
rand() / ( RAND_MAX / TYPES_OF_TILES + !!(RAND_MAX % TYPES_OF_TILES))
OTOH using someone else's code that does the same thing is always better.
Your best bet is to use a uniform distribution method of the same
random number generator implementation. There is std.random.uniform()
in D2's Phobos which serves this purpose. If you don't have an
equivalent, your next stop is "rand() % TYPES_OF_TILES". It's not
strictly uniform but close if TYPES_OF_TILES is small.
if TYPES_OF_TILES is to small (like 4) it start s getting highly un random
again.
