There are certain times when you'd like an ASP script to randomly choose to do one of N
tasks. One can use the Randomize
statement and the Rnd
function
in VBScript to select a random number. In fact, this is the only way to generate truly
random numbers. But sometimes generating a purely random number isn't that important, you
would just like to do 1 of N things, where each of the N events are equally probable.
For examle, on the 4GuysFromRolla.com homepage I have a space reserved to place a link to one of my two books: Designing Active Server Pages and Sams Teach Yourself ASP 3.0 in 21 Days. I wanted to randomly have each book displayed... however, I am not too concerned about true randomness and am more interested in having each book shown with equal probability.
It struck me that a very easy thing to do would be to determine the current time (using
the Time
function), grab the seconds (using the Second
function)
and then Mod 2
the result. The Mod
operator is used like:
Number1 Mod Number2

dividing Number1
and Number2
and returning the
remainder. Here is a simple chart of Mod
values:
Mod Values  

Number1  Number2 
Number1 Mod Number2 
So, to give two events the same probability, I simply did:

That's all there is to it! A quick and dirty way to act on one of two events with equal probability!
Is that Number Even or Odd? 

The Mod operator can be used to quickly determine if a number is even
or odd! Assume we have some integer value, iVal . If iVal Mod 2 = 0
then iVal is even; if, on the other hand, iVal Mod 2 = 1 , then
iVal is odd!

Happy Programming!
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