Lisp tính cao độ

;TINH CAO DO NHAP KHOANG CACH VA VIET VAO DIEM CHON (tạo một block caodo.dwg)
(defun c:tcd1 ()
  (c:setupdesign)
  (setq luu (getvar "osmode"))
  (setvar "osmode" 33)
  (initget 3)
  (setq pt1 (getpoint "\nChon diem goc da biet cao do: " ))
  (setq pt2 (getpoint "\nChon diem can tim cao do: " pt1))

;  (setq pt3 (getreal "\nVao cao do diem da biet:" ))
  (setvar "blipmode" 0)
  (while (null (setq chon (entsel "\nChon so cao do diem truoc:"))))
  (setq dt (entget (car chon)))
  (setq loai (cdr (assoc 0 dt)))
  (if (= loai "TEXT")
      (progn
            (setq gtri (cdr (assoc 1 dt)))

                      (setq pt3 (atof gtri))
                      (initget 0)
                          )
                          (progn
            )
            )

;  (setq B (getreal "\nCao do ghi ben trai (0) hay phai (1) ? : "))
  (setq B 1) 
  (setq dau1 (car pt1))
  (setq cuoi1 (cadr pt1))
  (setq dau2 (car pt2))
  (setq cuoi2 (cadr pt2))
  (setq l (abs (- dau1 dau2)))
  (Setq phia (- 0 0))
  (setq xt (+ dau2 1.10))
  (setq yt (- cuoi2 0.45))
  (setq cht (list xt yt))
  (setq xp (- dau2 1.10))
  (setq yp (- cuoi2 0.45))
  (setq chp (list xp yp))

  (if ( = B phia )
  (command "insert" "cdt" pt2 "" "" "0")
  (command "text" "J" "M" cht "0.36" "0" (rtos (+ pt3 (/ (- cuoi2 cuoi1) ntl)) 2 tphan))
  )
  (if ( > B phia )
  (command "insert" "cdo" pt2 "" "" "0")
  (command "text" "J" "M" chp "0.36" "0" (rtos (+ pt3 (/ (- cuoi2 cuoi1) ntl)) 2 tphan))
  )
  (setvar "osmode" luu)
;  (setvar "blipmode" luublipmode)

  (setq pt3 nil)
  (princ)
  )
  ;het tcd