I am going to create an MS Excel program that calculates odds of
horses coming in different places given the probability of each coming
in first using the Harville formula. I would like to create my
program so that it can accommodate different numbers of horses in the
race. I'm pretty certain that I can figure out how to make up a
program so that I have a subroutine to figure out the probability of
each place but I don't know if I know the best way to create one
subroutine that would calculate the probability for all horses for all
places.

From what I can tell, I would have to have the program change the code
on the fly to add variables for each new place. If I wanted to create
code on the fly, I could use code similar to what is at the bottom of
the following link: http://www.ozgrid.com/forum/showthread.php?t=66426.
Do you have any suggestions?

Your response is appreciated.