FUNCTION FAC(N)
C***BEGIN PROLOGUE  FAC
C***DATE WRITTEN   770601   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  C1
C***KEYWORDS  FACTORIAL,SPECIAL FUNCTION
C***AUTHOR  FULLERTON, W., (LANL)
C***PURPOSE  Computes the factorial of N.
C***DESCRIPTION
C
C FAC(N) evaluates the factorial function of N.  FAC is single
C precision.  N must be an integer between 0 and 25 inclusive.
C***REFERENCES  (NONE)
C***ROUTINES CALLED  GAMLIM,R9LGMC,XERROR
C***END PROLOGUE  FAC