/* fac.q: faculty function */

fac N			= N*fac(N-1) if N>0;
			= 1 otherwise;

/* iterative version */

private itfac2;

itfac N			= itfac2 1 N;
itfac2 P I		= itfac2 (P*I) (I-1) if I>0;
			= P otherwise;