static private long fac1(int j){
  long i=j;
  if (j < 0)   i=Math.abs(j);
  if (i > longFactorials.length)   throw new IllegalArgumentException("Overflow");
  long d=1;
  while (i > 1)   d*=i--;
  if (j < 0)   return -d;
 else   return d;
}

static private long fac1 ( int j ) { long i = j ; if ( j < 0 ) i = Math . abs ( j ) ; if ( i > longFactorials . length ) throw new IllegalArgumentException ( "Overflow" ) ; long d = 1 ; while ( i > 1 ) d *= i -- ; if ( j < 0 ) return - d ; else return d ; }
returns the factorial of the argument .
