In the exercises in chapter 6, you created a class named purchase. each purchase contains an invoice number, amount of sale, amount of sales tax, and several methods. now, write a program that declares an array of five purchase objects and prompt a user for their values. as each purchase object is created, continuously prompt until the user enters an invoice number between 1000 and 8000 inclusive and a non-negative sale amount. prompt the user for values for each object and then display all the value