How to draw circle in Autolisp

 Command: CIRCLE

    Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: 2P

    Specify first end point of circle's diameter: pick point
    Specify second end point of circle's diameter: pick point

LISP Program Example -

    (command "CIRCLE" "2P" PT1 PT2)    ;using previously set start and end points

Example:

(defun c:circle()

   (setq PT1(strcat "0" "," "0"))               ;set start point

    (setq PT2(strcat "2000" "," "0"))         ;set end point

    (command "LINE" PT1 PT2 "")             ;issue LINE command to AutoCAD, draw from PT1 to PT2

    (command "CIRCLE" "2P" PT1 PT2)      ;Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: Pick center point 
                                                       ;issue the CIRCLE command to AutoCAD,Draw from PT1 to PT2 .

  )