圆改成正多边形 ，lsp

;;;;圆改成正多边形
(defun c:15demo3()
(setvar "cmdecho" 0)
(setq  osm (getvar "osmode"))
( setvar "osmode" 0)
(princ "\n选择要改的圆变成正多边形：")
(setq p1 (getpoint))
(setq p2 (getcorner p1))  
(if (> (car p1) (car P2))
(setq ss (ssget "c" p1 p2))
(setq ss (ssget "w" p1 p2))
  )
(setq side (getint "\n正多边形的边数<5>:"))
  (if (= side  nil) (setq side  5))
  (initget "C c I i")
  (setq ttype (getkword "\n内接于圆(I)/外切于圆(C)<I>:"))
  (if (= ttype nil)(setq ttype "i"))
(setq n 0)
(repeat (sslength ss)
(setq ent (ssname ss n))
(setq ent_data (entget ent))
(setq ent_type (cdr (assoc 0 ent_data)))
(if (= ent_type "CIRCLE")
(progn
(setq r (cdr (assoc 40 ent_data)))
(setq pc (cdr(assoc 10 ent_data)))
(command "polygon" side pc ttype r)
)
)
(setq n (1+  n))
)
  (setvar "osmode" osm)
  
(princ )
)

cad的底层语言autolisp