From 5c282d60b06c032623a8a2d46ebded05a1eb06a2 Mon Sep 17 00:00:00 2001 From: lakegreene Date: Wed, 8 Jul 2020 17:22:17 -0400 Subject: [PATCH] Complete exercises on README.md --- README.md | 30 ++++++++++++++++++++++++++++-- bluej.pkg | 50 ++++++++++++++++++++++++++++++-------------------- package.bluej | 50 ++++++++++++++++++++++++++++++-------------------- 3 files changed, 88 insertions(+), 42 deletions(-) diff --git a/README.md b/README.md index ee11f2c..a1e610d 100644 --- a/README.md +++ b/README.md @@ -22,12 +22,15 @@ Work through all these exercises. You edit this file with your answers for these ### Exercise 2.2 * What value is returned if you check the machine’s balance after it has printed a ticket? +>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? + >No refund is provided nor an additional ticket; the machine's balance is reset after printing * What happens if you do not insert enough and then try to print a ticket? + >A ticket is printed ### 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. @@ -36,9 +39,12 @@ Work through all these exercises. You edit this file with your answers for these * Create another ticket machine for tickets of a different price. * Buy a ticket from that machine. * Does the printed ticket look different? + >Yes. The ticket price and the total are different for each instance of TicketMachine ### 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
@@ -46,11 +52,15 @@ Does it matter whether we write
or
`class public TicketMachine`
in the outer wrapper of a class? +>Yes, the latter will not compile * 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? + >Yes, red, slanted lines appeared on both the TicketMachine and TicketMachine Test classes * What error message do you get when you now press the compile button? + >"invalid method declaration; return type required" * 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. @@ -58,10 +68,15 @@ in the outer wrapper of a 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. + >fields: price, balance, total, ticketNumber + >constructors: TicketMachine + >methods: getPrice, getTicketNumber, getBalance, insertMoney, calculateTotal, incrementTicketNumber, printTicket * 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? +>Does not contain the return keyword +>Does not include output type ### Exercise 2.11 * What do you think is the type of each of the following fields? @@ -71,6 +86,7 @@ private int count; private Student representative; private Server host; ``` +>int, Student, Server respectively ### Exercise 2.12 * What are the names of the following fields? @@ -80,6 +96,8 @@ private boolean alive; private Person tutor; private Game game; ``` +>alive, tutor, game respectively + ### Exercise 2.13 In the following field declaration from the TicketMachine class
@@ -88,35 +106,43 @@ In the following field declaration from the TicketMachine class
private int price; ``` does it matter which order the three words appear in? +>Yes + * 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? + * Does the appearance of the class diagram after each change give you a clue as to whether or not other orderings are possible? + >Yes * 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`. +>int 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, double respectively ### Exercise 2.18 * Can you guess what types some of the `Book` class’s fields might be? +>String, double * Can you assume anything about the names of its fields? +>Yes, they may be "title" or "price" or something referencing either of those ideas READ upto and INCLUDING section 2.15 of this chapter. diff --git a/bluej.pkg b/bluej.pkg index bf25784..c42b720 100644 --- a/bluej.pkg +++ b/bluej.pkg @@ -1,20 +1,23 @@ #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 +dependency1.from=TicketMachineTest +dependency1.to=TicketMachine +dependency1.type=UsesDependency +editor.fx.0.height=844 +editor.fx.0.width=676 +editor.fx.0.x=-60 +editor.fx.0.y=-1057 +objectbench.height=294 +objectbench.width=442 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 +package.divider.vertical=0.5813630041724618 +package.editor.height=411 +package.editor.width=348 +package.editor.x=0 +package.editor.y=23 +package.frame.height=777 +package.frame.width=466 +package.numDependencies=1 +package.numTargets=2 package.showExtends=true package.showUses=true project.charset=UTF-8 @@ -24,9 +27,16 @@ readme.width=47 readme.x=10 readme.y=10 target1.height=50 -target1.name=TicketMachine +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=10 +target1.y=110 +target2.height=50 +target2.name=TicketMachine +target2.showInterface=false +target2.type=ClassTarget +target2.width=120 +target2.x=80 +target2.y=50 diff --git a/package.bluej b/package.bluej index bf25784..c42b720 100644 --- a/package.bluej +++ b/package.bluej @@ -1,20 +1,23 @@ #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 +dependency1.from=TicketMachineTest +dependency1.to=TicketMachine +dependency1.type=UsesDependency +editor.fx.0.height=844 +editor.fx.0.width=676 +editor.fx.0.x=-60 +editor.fx.0.y=-1057 +objectbench.height=294 +objectbench.width=442 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 +package.divider.vertical=0.5813630041724618 +package.editor.height=411 +package.editor.width=348 +package.editor.x=0 +package.editor.y=23 +package.frame.height=777 +package.frame.width=466 +package.numDependencies=1 +package.numTargets=2 package.showExtends=true package.showUses=true project.charset=UTF-8 @@ -24,9 +27,16 @@ readme.width=47 readme.x=10 readme.y=10 target1.height=50 -target1.name=TicketMachine +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=10 +target1.y=110 +target2.height=50 +target2.name=TicketMachine +target2.showInterface=false +target2.type=ClassTarget +target2.width=120 +target2.x=80 +target2.y=50