(defun c:cp (/ ss cp n ns) (vl-load-com)
  (if (setq ss (ssget (list (cons 0 "circle"))))
    (if (setq cp (getdist "\nEnter value:"))
      (progn
        (vla-startundomark (vla-get-activedocument (vlax-get-acad-object)))
        (repeat (setq n (sslength ss))
          (setq ns (vlax-ename->vla-object (ssname ss (setq n (1- n)))))
          (vla-put-Radius ns (+ (vla-get-Radius ns) (/ cp 2)))
        )
        (vla-endundomark (vla-get-activedocument (vlax-get-acad-object)))
      )
    )
  ) (princ)
)