coyote: CGSETDIFFERENCE

Description
This function is used to find the difference between two sets of integers.
In other words, the function will find the values that are in Set A but
are missing in Set B.
Categories
Utilities
Returns
A vector of values that are found in set_a but are missing in set_b.
Params
set_a: in, required, type=integer
   A vector of integers.
set_b: in, required, type=integer
   A vector of integers.
Keywords
count: out, optional, type=integer
     This keyword contains the number of elements in the difference vector.
noresult: in, optional
     Set this keyword to a value that will be returned from the function
     if no difference between the two sets of numbers is found. By default, set_a.
positions: out, optional, type=integer
     An output keyword that will return the positions or locations in A of the values
     not found in B.
success: out, optional, type=boolean
     This keyword is set to 1 if an difference was found, and to 0 otherwise.
Examples
Here is how to use this program::
  IDL> set_a = [1,2,3,4,5]
  IDL> set_b = [4,5,6,7,8,9,10,11]
  IDL> Print, cgSetDifference(set_a, set_b)
      1  2  3 
Author
FANNING SOFTWARE CONSULTING::
   David W. Fanning
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: david@idlcoyote.com
   Coyote's Guide to IDL Programming: http://www.idlcoyote.com
History
Change History::
   Written by: David W. Fanning, November 25, 2009, from code originally supplied to the IDL
      newsgroup by Research Systems software engineers.
   Added COUNT and POSITIONS keywords. Liam Steele, 13 Dec 2012.
   Defined values for COUNT and POSITIONS when there is no overlap in the vectors. 14 Dec 2012. LS.
Copyright
Copyright (c) 2009-2013, Fanning Software Consulting, Inc.