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The second Objects lab,from the BlueJ book's second chapter.
Look for the Chapter 2 file you need in the doc folder. There is 35 pages of reading and exercises in the chapter.
Work through all these exercises. You edit this file with your answers for these exercises.
Exercise 2.5 Create another ticket machine for tickets of a different price. Buy a ticket from that machine. Does the printed ticket look different?
Exercise 2.6 Write out what you think the outer wrappers of the Student and LabClass classes might look like – do not worry about the inner part.
Exercise 2.7 Does it matter whether we write
public class TicketMachine
or
class public TicketMachine
in the outer wrapper of a class? Edit the source of the TicketMachine class to
make the change and then close the editor window. Do you notice a change in the
class diagram?
What error message do you get when you now press the Compile button? Do you think
this message clearly explains what is wrong?
Exercise 2.8 Check whether or not it is possible to leave out the word public from the outer wrapper of the TicketMachine class.
Exercise 2.9 From your earlier experimentation with the ticket machine objects within BlueJ you can probably remember the names of some of the methods – printTicket, for instance. Look at the class definition in Code 2.1 and use this knowledge, along with the additional information about ordering we have given you, to try to make a list of the names of the fields, constructors, and methods in the TicketMachine class. Hint: There is only one constructor in the class. Exercise 2.10 Do you notice any features of the constructor that make it significantly different from the other methods of the class?
Exercise 2.11 What do you think is the type of each of the following fields?
private int count;
private Student representative;
private Server host;
Exercise 2.12 What are the names of the following fields?
private boolean alive;
private Person tutor;
private Game game;
Exercise 2.13 In the following field declaration from the TicketMachine class
private int price;
does it matter which order the three words appear in? Edit the TicketMachine class to try different orderings. After each change, close the editor. Does the appearance of the class diagram after each change give you a clue as to whether or not other orderings are possible? Check by pressing the Compile button to see if there is an error message. Make sure that you reinstate the original version after your experiments!
Exercise 2.14 Is it always necessary to have a semicolon at the end of a field declaration? Once again, experiment via the editor. The rule you will learn here is an important one, so be sure to remember it.
Exercise 2.15 Write in full the declaration for a field of type int whose name is status.
Exercise 2.16 To what class does the following constructor belong?
public Student(String name)
Exercise 2.17 How many parameters does the following constructor have and what are their types?
public Book(String title, double price)
Exercise 2.18 Can you guess what types some of the Book class’s fields might be? Can you assume anything about the names of its fields?
Work all Exercises from 2.19 to 2.58 that are NOT marked Challenge exercise. READ upto and INCLUDING section 2.15 of this chapter.