CAD中求面积及周长的小程序 (lsp)

;;我来公开源程序，我有版权。copyright(c)1998~2005 (defun c:mj (/ os pt1 a)
(setq os (getvar "osmode"))
(setvar "osmode" 512)
(setq pt1 (getpoint "n１、请在封闭区域的边界上任选一点："))
(setvar "osmode" os)
(prompt "n２、请将封闭区域的所有边界加入到选择集中：")
(setq a (ssget))
(if (= (sslength a) 1)
(command "area" "e" a)
)
(if (> (sslength a) 1)
(progn
(command "pedit" pt1 "y" "j" a "" "")
(command "area" "e" pt1)
(command "explode" pt1)
)
)
)