Combin

Calculates the number of combinations for a given set of data.

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Interface
Combin
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Interface

C++

Combin

doublecombin(	int	`n`
	int	`k`	)

Returns the number of combinations for a given number of items. Use Combin to determine the total possible number of groups for a given number of items. A combination is any set or subset of items, regardless of their internal order. Combinations are distinct from permutations, for which the internal order is significant. The number of combinations of n items with k items in each combination is given by the following formula:

$C(N,k)=\frac{P(N,k)}{k!}=\frac{N!}{K!(N-k)!}$

(2)

where:

$P(N,k)=\frac{N!}{(N-k)!}$

(3)

Example 1

#include <codecogs/statistics/moments/combin.h>
#include <iostream>
int main()
 {
   double com = Stats::Moments::combin(9, 5);
   std::cout << "The number of combinations is: " << com << std::endl;
  return 0;
}

Output:

The number of combinations is: 126

Parameters

n	the total number of items.
k	the number of items in each combination. k must be less than n.

Returns

the number of combinations for a given number of items

Authors

Anca Filibiu (August 2005)

Source Code

Source code is available when you agree to a GP Licence or buy a Commercial Licence.

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