E8.18 Implement Coin and CashRegister classes as described in Exercise E8.1. Place the classes into a package called money. Keep the CashRegisterTester class in the default package. E8.19 Place a BankAccount class in a package whose name is derived from your e-mail address, as described in Section 8.6. Keep the BankAccountTester class in the default package. E9.1 Implement a subclass of Bank Account called BasicAccount whose withdraw method will not withdraw more money than is currently in the account. E9.2 Implement a subclass of BankAccount called Basic Account whose withdraw method charges a penalty of S30 for each withdrawal that results in an overdraft. E9.3 Reimplement the CheckingAccount class from How To 9.1 so that the first overdraft in any given month incurs a $20 penalty, and any further overdrafts in the same month result in a S30 penalty. E9.8 Add a class MultiChoiceQuestion to the question hierarchy of Section 9.1 that allows multiple correct choices. The respondent should provide all correct choices, separated by spaces. Provide instructions in the question text. E10.18 Enhance the Button Viewer program so that it has two buttons, each of which prints a message "I was clicked n times!" whenever the button is clicked. Each button should have a separate click count. E10.19 Enhance the Button Viewer program so that it has two buttons labeled A and B, cach of which prints a message "Button x was clicked!", where x is A or B. E11.2 Write a program that reads a file, removes any blank lines, and writes the non-blank lines back to the same file