(defun chint (a b c cint n) (declare (type double-float a))
 (declare (type double-float b))
 (declare (type (simple-array double-float (*)) c))
 (declare (type (simple-array double-float (*)) cint))
 (declare (type fixnum n))
 (prog ((j 0) (fac 0.0d0) (sum 0.0d0) (con 0.0d0)) (declare (type fixnum j))
  (declare (type double-float fac)) (declare (type double-float sum))
  (declare (type double-float con)) (setf con (* 0.25 (+ b (- a))))
  (setf sum 0.0) (setf fac 1.0)
  (fdo ((j 2 (+ j 1))) ((> j (+ n (- 1))) nil)
   (tagbody
    (fset (fref cint j)
     (/ (* con (+ (fref c (+ j (- 1))) (- (fref c (+ j 1))))) (+ j (- 1)))
    )
    (setf sum (+ sum (* fac (fref cint j)))) (setf fac (- fac))
  ))
  (fset (fref cint n) (/ (* con (fref c (+ n (- 1)))) (+ n (- 1))))
  (setf sum (+ sum (* fac (fref cint n)))) (fset (fref cint 1) (* 2.0 sum))
  (return (values a b c cint n))
))