diff --git a/README.md b/README.md index ee11f2c..fd3aecc 100644 --- a/README.md +++ b/README.md @@ -18,27 +18,39 @@ Work through all these exercises. You edit this file with your answers for these * Use `getPrice` method to view the value of the price of the tickets that was set when this object was created. * Use `insertMoney` method to simulate inserting an amount of money into the machine. * Use `getBalance` to check that the machine has a record of the amount inserted. - * You can insert several separate amounts of money into the machine, just like you might insert multiple coins or notes into a real machine. Try inserting the exact amount required for a ticket. As this is a simple machine, a ticket will not be issued automatically, so once you have inserted enough money, call the `printTicket` method. A facsimile ticket should be printed in the BlueJ terminal window. + * You can insert several separate amounts of money into the machine, just like you might insert multiple coins or notes into a real machine. Try inserting the exact amount required for a ticket. As this is a simple machine, a ticket will not be issued automatically, so once you have inserted enough money, call the `printTicket` method. A facsimile ticket should be printed in the BlueJ terminal window. ### Exercise 2.2 * What value is returned if you check the machine’s balance after it has printed a ticket? +* - Its 0. ### Exercise 2.3 * Experiment with inserting different amounts of money before printing tickets. - * Do you notice anything strange about the machine’s behavior? - * What happens if you insert too much money into the machine – do you receive any refund? - * What happens if you do not insert enough and then try to print a ticket? + * Do you notice anything strange about the machine’s behavior? + * - The balance is always 0 after purchasing a ticket. + * What happens if you insert too much money into the machine – do you receive any refund? + * - NO :( + * What happens if you do not insert enough and then try to print a ticket? + * - You still get a ticket. ### Exercise 2.4 * Try to obtain a good understanding of a ticket machine’s behavior by interacting with it on the object bench before we start looking at how the `TicketMachine` class is implemented in the next section. ### 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? + * Buy a ticket from that machine. + * Does the printed ticket look different? + * - No ### 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. +* - public class Student { + + } + + public class LabClass { + + } ### Exercise 2.7 Does it matter whether we write
@@ -46,26 +58,34 @@ Does it matter whether we write
or
`class public TicketMachine`
in the outer wrapper of a class? +- Yes! The second way is wrong and will not work. * 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? + * Do you notice a change in the class diagram? + * - Unable to compile + * What error message do you get when you now press the compile button? + * - Illegal start of expression + * Do you think this message clearly explains what is wrong? + * - No ### Exercise 2.8 * Check whether or not it is possible to leave out the word `public` from the outer wrapper of the `TicketMachine` class. - +- Yes and it will be assumed as `private` or protected. ### 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. + * 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. + * Fields: price, balance, total, ticket number. + * Constructor: TicketMachine. + * Methods: getPrice(), getTicketNumber(), getBalance(), insertMoney(Integer amount), calculateTotal(), incrementTicketNumber(), printTicket(). ### Exercise 2.10 * Do you notice any features of the constructor that make it significantly different from the other methods of the class? +* - It takes an input Int ticketCost and sets that as the price. ### Exercise 2.11 * What do you think is the type of each of the following fields? - +- int, Student, Server. ```java private int count; private Student representative; @@ -74,7 +94,7 @@ private Server host; ### Exercise 2.12 * What are the names of the following fields? - +- alive, tutor, game. ```java private boolean alive; private Person tutor; @@ -88,35 +108,43 @@ In the following field declaration from the TicketMachine class
private int price; ``` does it matter which order the three words appear in? +-Yes, they have to appear exactly in that order. + * 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 reinstantiate the original version after your experiments! + * Does the appearance of the class diagram after each change give you a clue as to whether or not other orderings are +possible? -No + * Check by pressing the compile button to see if there is an error message. + * Make sure that you reinstantiate the original version after your experiments! ### Exercise 2.14 * Is it always necessary to have a semicolon at the end of a field declaration? +* - Yes * 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`. +* private Integer status ### Exercise 2.16 * To what class does the following constructor belong? ``` public Student(String name) ``` +- Student ### Exercise 2.17 * How many parameters does the following constructor have and what are their types? ``` public Book(String title, double price) ``` +2, string and double. ### Exercise 2.18 * Can you guess what types some of the `Book` class’s fields might be? +* - Integer, string * Can you assume anything about the names of its fields? +* - They can include pages, title, author, etc. READ upto and INCLUDING section 2.15 of this chapter. diff --git a/bluej.pkg b/bluej.pkg index bf25784..f7a23a7 100644 --- a/bluej.pkg +++ b/bluej.pkg @@ -1,32 +1,48 @@ #BlueJ package file -editor.fx.0.height=722 -editor.fx.0.width=800 -editor.fx.0.x=709 -editor.fx.0.y=113 -objectbench.height=101 -objectbench.width=461 -package.divider.horizontal=0.6 -package.divider.vertical=0.8007380073800738 -package.editor.height=427 -package.editor.width=674 -package.editor.x=1067 -package.editor.y=119 -package.frame.height=600 -package.frame.width=800 -package.numDependencies=0 -package.numTargets=1 +dependency1.from=TicketMachineTest +dependency1.to=TicketMachine +dependency1.type=UsesDependency +editor.fx.0.height=703 +editor.fx.0.width=719 +editor.fx.0.x=558 +editor.fx.0.y=25 +objectbench.height=164 +objectbench.width=390 +package.divider.horizontal=0.6006051437216339 +package.divider.vertical=0.7020905923344948 +package.editor.height=396 +package.editor.width=564 +package.editor.x=571 +package.editor.y=25 +package.frame.height=638 +package.frame.width=681 +package.numDependencies=1 +package.numTargets=3 package.showExtends=true package.showUses=true project.charset=UTF-8 -readme.height=58 +readme.height=60 readme.name=@README -readme.width=47 +readme.width=48 readme.x=10 readme.y=10 -target1.height=50 -target1.name=TicketMachine +target1.height=70 +target1.name=TicketMachineTest target1.showInterface=false -target1.type=ClassTarget -target1.width=120 -target1.x=80 -target1.y=50 +target1.type=UnitTestTargetJunit4 +target1.width=130 +target1.x=140 +target1.y=110 +target2.height=50 +target2.name=TicketMachine +target2.showInterface=false +target2.type=ClassTarget +target2.width=120 +target2.x=80 +target2.y=50 +target3.height=70 +target3.name=README.md +target3.type=TextTarget +target3.width=120 +target3.x=10 +target3.y=110 diff --git a/package.bluej b/package.bluej index bf25784..f7a23a7 100644 --- a/package.bluej +++ b/package.bluej @@ -1,32 +1,48 @@ #BlueJ package file -editor.fx.0.height=722 -editor.fx.0.width=800 -editor.fx.0.x=709 -editor.fx.0.y=113 -objectbench.height=101 -objectbench.width=461 -package.divider.horizontal=0.6 -package.divider.vertical=0.8007380073800738 -package.editor.height=427 -package.editor.width=674 -package.editor.x=1067 -package.editor.y=119 -package.frame.height=600 -package.frame.width=800 -package.numDependencies=0 -package.numTargets=1 +dependency1.from=TicketMachineTest +dependency1.to=TicketMachine +dependency1.type=UsesDependency +editor.fx.0.height=703 +editor.fx.0.width=719 +editor.fx.0.x=558 +editor.fx.0.y=25 +objectbench.height=164 +objectbench.width=390 +package.divider.horizontal=0.6006051437216339 +package.divider.vertical=0.7020905923344948 +package.editor.height=396 +package.editor.width=564 +package.editor.x=571 +package.editor.y=25 +package.frame.height=638 +package.frame.width=681 +package.numDependencies=1 +package.numTargets=3 package.showExtends=true package.showUses=true project.charset=UTF-8 -readme.height=58 +readme.height=60 readme.name=@README -readme.width=47 +readme.width=48 readme.x=10 readme.y=10 -target1.height=50 -target1.name=TicketMachine +target1.height=70 +target1.name=TicketMachineTest target1.showInterface=false -target1.type=ClassTarget -target1.width=120 -target1.x=80 -target1.y=50 +target1.type=UnitTestTargetJunit4 +target1.width=130 +target1.x=140 +target1.y=110 +target2.height=50 +target2.name=TicketMachine +target2.showInterface=false +target2.type=ClassTarget +target2.width=120 +target2.x=80 +target2.y=50 +target3.height=70 +target3.name=README.md +target3.type=TextTarget +target3.width=120 +target3.x=10 +target3.y=110