"Dan." wrote:
> 
> hi, i'm sorry to bother you; but i was wondering what the function of the OR
> operator was in terms of numbers:
> 
>     num0 = num1 or num2
> 

Think of it in terms of the actual bits used by 
the computer. Any bit position that has a 1 in
either input number will have a 1 in the output 
number:

num1	1011 (11)	0000 (0)
num2 OR 0110  (6)   OR  0110 (6)
	----		----
num0	1111 (15)	0110 (6)

AND works the opposite; any bit position that 
doesn't have both 1's will output 0:

	1011 (11)	1111 (15)
   AND	0000  (0)  AND	0010  (2)
	----		----
	0000  (0)	0010  (2)

--------------------------------------------

'Bitmasking', as it's called, can be useful if 
you have a lot of yes/no type data to store
really compactly.

Let's say we have an 8-bit variable CarData;
each bit can represent some feature that is
or is not found on a particular car:

stock/enhanced CD player------
sport package---------------  |
power steering------------  | |
power door locks--------  | | |
convertible-----------  | | | |
turbocharger--------  | | | | |
leather seats-----  | | | | | |
ABS-------------+ | | | | | | |
		0 0 0 0 0 0 0 0

Let's say we have a car with a stock CD player
(its CarData bit 1 is 0), and we want to indicate
that it now has the enhanced player (bit 1 = 1).
BUT, we don't want any other car info to change!

if CarData and 1 = 0 then 'test the value of bit 1
  CarData = CarData or 1 'CarData bit 1 is now 1
end if

This is how you set a single bit to zero without
changing any other bits - AND it with a zero bit:

		10000101 (133)
	  AND	11111110 (254)
		--------
		10000100 (132)

if CarData and 1 = 1 then
  CarData= CarData and 254 'only the value of bit 1 changes
end if



Clear as mud?  ;-)
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