CFLib.org – Common Function Library Project

Description:
Returns the Combination of n elements taken p at a time.

Return Values:
Returns a simple value

Example:

<CFSET n=13>
  <CFSET p=2>
  <CFOUTPUT>
  Given n=13, p=2
  Combination(n,p) is #Combination(n,p)#
  </CFOUTPUT>

Parameters:

Full UDF Source:

/**
 * Returns the Combination of n elements taken p at a time.
 * This funciton requires the Permutation() and Factorial() functions from this library.
 * 
 * @param n      Any non-negative integer 
 * @param p      any non-negative integer, <= n 
 * @return Returns a simple value 
 * @author Joel Cox (jlcox@goodyear.com) 
 * @version 1, July 18, 2001 
 */
function Combination(n,p)
{
  var RetVal = 0;
  if (p GT n) {
   RetVal = "undefined";
  }
  else
   RetVal = Permutation(n,p) / Factorial(p);  
  Return RetVal;
}