thkyou mam..finally section 18 clear ho gya..thanks a lot ..u r best teacher koi b teacher student k chote chote problems p gor nai krte bt ap choti si problem ko solve krne k liy b kfi effort lgati h..thnku so much..apke wjh s cpc clear hua h or ap bst pdhaate h.and apka example b aacha hota h
