#!/usr/bin/gcl -f

(defun printResult ( a b c x)
    (let
        (
            (bSign "+")
            (cSign "+")
        )
        (if (< b 0) (setf bSign "") ())
        (if (< c 0) (setf cSign "") ())
        (format t
            "For ~A*x^2 ~A ~A*x ~A ~A = 0 You can find ~A.~%"
            a
            bSign b
            cSign c
            x
        )
    )
)

(defun calcX (a b c)
    (let
        (
            (d 0)
            (x 0)
        )
        (setf d (- (* b b) (* 4 a c)))
        (if (> d 0)
            (setq x
                (list
                    ( /
                        (+ b (sqrt d))
                        (* 2 a)
                    )
                    ( /
                        (- b (sqrt d))
                        (* 2 a)
                    )
                )
            )
            (if (eql d 0)
                (setq x
                    (list
                        (/
                            (- b)
                            (* 2 a)
                        )
                    )
                )
                (setq x () )
            )
        )
        x
    )
)

(defun square ()
    (format t "a*x^2 + b*x + c = 0~%")

    (let
        (
            (a 0)
            (b 0)
            (c 0)
            (x 0)
        )
        (format t "a=")
        (setf a (read))
        (format t "b=")
        (setf b (read))
        (format t "c=")
        (setf c (read))
        (setf x (calcX a b c))
        (printResult a b c x)
    )
)


(square)
(bye)