4. BOOK-IS-MY-BEST-FRIEND", one of the leading book shops in your locality needs a program that will help them to calculate the value of the books and the discount. Program should use a class Book which will have the following members. Member variables: quantity, price. Member Methods: to set quantity and price to calculate and return the value of book which is price* quantity. to calculate & return discount which is 5% of value if value 1000 and 7.5% of Value if value > 1000 and