factorial2 Function

public pure function factorial2(n, n2) result(f)

factorial(n,m) = m! / n! for n < m = 1 otherwise thus, factorial(1,2) = 2; factorial(2,1) = 1

Type	Intent	Optional	Attributes		Name
integer,	intent(in)			::	n
integer,	intent(in),	optional		::	n2