NTTL Function - Binomial

Description

Compute n choose k, the binomial coefficient.

The algorithm is based on the formula:

Binomial( n, k ) = n! / ( k! (n-k)! )

We determine whether k or (n - k) is larger, and use the larger value to cancel the numerator. This should lead to a minimum number of multiplications.

Header

<nttl/binomial.h>

Signature

template< class T >
void Binomial( T *Value, size_t n, size_t k )

Parameters

Name	Type	Description
Value	T *	Pointer to the result.
size_t	n
size_t	k

Returns

( none )

Example

#include <nttl/binomial.h> ... long b; Binomial( &b, 5, 2 ); cout << "(5,2) = " << b << endl;