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This is probably an oversimplification, but I
think of 0 as an integer with a value of zero and Null as "no
value." As an example, suppose you had an array of C with holes in the
data. Those holes are Nulls. Take a look at the Nz function
which converts Null values to 0. I believe, in general, calculations
involving Null produce Null and conditional statements containing Null produce
False. As for the variables, I would initialize all to 0. (I'm
sure if this is not correct someone will jump in and straighten things
out).
Bill
----- Original Message -----
Sent: Friday, September 12, 2008 9:03
PM
Subject: [amibroker] Difference between 0
and Null for variables?
Tried to do a search in the User's Guide for this, but can't quite
pinpoint an explanation:
What is the difference, if any, between 0 and Null when assigning
non-boolean variables? When should we use Null instead of plain old 0?
For example, all of the six variables below are real numbers, yet some
are initially set to Null and others to 0.
I copied this snippet from an example AFL that works properly:
// Set up variables for our entry values, as our stops will test
// against the initial entry prices
valueAtBuy = valueAtShort = Null;
profitLevel = profitLevel2 = Null;
// Number of open contracts
longContractCount = 0;
shortContractCount = 0;
for (i = start; i < BarCount; i++)
{
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