A Subclass - Intro to Java Programming Udacity Japanese English (auto-generated)

A Subclass - Intro to Java ProgrammingYouTube↗ IA↗(long shot)
Education 1.4K views 4 likes 0 dislikes 23 Feb 2015

Udacity 651K subscribers United States YouTube↗

Click to Play Video

Questionクラスを勉強したので今度はサブクラスを作成しましょう

we've just worked with a question class and now it's time to form a subclass

私たちはこうした選択問題を何度か見てきました

we've all seen these multiple choice questions as a question and there are

選択肢があってこう呼ばれますちなみにこの問題の答えを言っておくと

multiple choices hence the name by the way if you ever wondered what was the

Java言語の元々の名前はOakでした

original name of the java language there

平凡でつまらない名前だったため改名されましたさてこれらのテキストを

was oak which was a name of there was so dull and boring that they changed it now

すべてQuestionクラスに入れて答えを3番と設定することもできますが

of course one could put this entire text here into a question class and set the answer to the string three but that true

それこそ平凡でつまらないので選択問題を専門に扱う

would be dull and boring it would be

クラスを作成する方がいいでしょうそうすればこのように

better to have a class that specifically deals with multiple choice questions so

オブジェクトの宣言ができますまずはChoiceQuestionというクラスを作成します

that we could declare an object somewhat like this we make a choice question

ここでもテキストを設定する必要がありますが

that's what I'm calling this class we still need to set the text of course but

addChoiceメソッドを呼び出せば

then for the choices I want to be able to call a method that I call odd choice

特定の選択肢を追加できますそしてそれぞれに正誤を設定します

it adds a particular choice and then specifies whether it's false or true

ChoiceQuestionクラスを一から作成したくないので

when I formed the choice question class I don't want to start from scratch

作成済みのQuestionクラスからできるだけ継承します　では方法を説明します

I want to inherit as much as possible from the question class that's already written let's see how to do that I'll

ChoichQuestionクラスを定義してそれがQuestionクラスを

define the choice question class and then I specified that it extends the

拡張すると設定しますこれはJavaのキーワードでChoiseQuestionが

question class that's the Java keyword

Questionのサブクラスになることを示しますサブクラスの本体に

for denoting that choice question should become a subclass of question into the

スーパークラスではなくサブクラスに存在するどんな新しいメソッドも入れます

body of the subclass I put in any new methods that are present in the subclass but not the superclass such as the add

例えばaddChoiceメソッドですまたサブクラスで変更が必要な

choice method he also put in the

メソッドの実装も行います例えばdisplayメソッドは変更が必要です

implementations of any methods that needed to change in the subclass for

ChoiceQuestionの表示は選択肢も表示するためです

example we'll need to change the display method since displaying a choice

最後にはもちろんインスタント変数を追加する必要があります

question must also display the choices and finally you of course need to add

ChoiceQuestionクラスがその機能を果たす変数です今回の場合それは

any instance variables that the choice question class needs to do its job in our case that would be the list of the

選択肢のリストです　ここでは含めない物もあります　サブクラスを定義する時

choices the key point is what you don't put in here when you define a subclass

問題なく実行できるスーパークラスのメソッドは

you never include any of the methods

インクルードしません例えばsetTextメソッドは問題なく実行できるため

from the superclass that worked just fine for example the set text method

スーパークラスから継承できますスーパークラスのフィールドも

will work fine and we can simply inherit it from the superclass also you don't

インクルード不要です　自動的に取得するので

want to include any fields from the superclass you get those automatically and if you

インクルードすると重複してしまいよくありませんここに入れるのは

were to include them again you'd get twice which is not good the point is

スーパークラスとは異なる部分ですサブクラスのメソッドは

that what you put inside here is the difference from the superclass

スーパークラスにまったくないか

everything that the subclass has that the superclass doesn't have at all or

同じような処理をしないものですではこれが具体的に

that it doesn't have in the same way let's have a closer look at exactly how that works for question

QuestionとChoiceQuestionにどう役立つでしょうか QuestionクラスとChoiceQuestionクラスです

and choice question here is our question class here is the choice question class

ChoiceQuestionクラスはどのメソッドを継承していますか

now have a close look and tell me which methods does the choice question class

該当するのはChoiceQuestionクラスで再定義されず

inherit just given me the names of all those methods that choice question

Questionクラスから単に取得されるすべてのメソッドです　ChoiceQuestionクラスは

doesn't redefine that it simply picks up from question which methods as choice

どのメソッドをオーバーライドするでしょうか再定義が必要なのは

question override that is which methods

Questionクラスのメソッドでは対応が不十分だからです

this choice question need to redefine because the ones from question are not satisfactory and finally which method or

最後にそもそもQuestionクラスにはなく

methods does choice question add that

ChoiceQuestionクラスが追加するメソッドは何でしょうか　メソッドの名前だけ書いてください

weren't present in the question class in the first place just give me the names of the methods altogether there five of

答えは全部で5つあります

Similar videos:

Another Pseudocode Example - Intro to Java Programming
Udacity
12.5K views 42 likes 9 dislikes 23 Feb 2015100% match

Downloading BlueJ - Intro to Java Programming
Udacity
23.5K views 40 likes 1 dislikes 23 Feb 2015100% match

Method Declarations - Intro to Java Programming
Udacity
5.8K views 18 likes 1 dislikes 23 Feb 2015100% match

Accessors and Mutators - Intro to Java Programming
Udacity
4.8K views 13 likes 0 dislikes 23 Feb 2015100% match

An Exercise on Variable Names - Intro to Java Programming
Udacity
4.7K views 3 likes 0 dislikes 23 Feb 2015100% match

Text and Numbers - Intro to Java Programming
Udacity
11.4K views 9 likes 0 dislikes 23 Feb 2015100% match

Algorithms 2 - Intro to Java Programming
Udacity
6.3K views 12 likes 1 dislikes 23 Feb 2015100% match

Average - Intro to Java Programming
Udacity
1.5K views 6 likes 3 dislikes 23 Feb 2015100% match

Hello, World - Intro to Java Programming
Udacity
18.4K views 34 likes 1 dislikes 23 Feb 2015100% match

Move to the First Yellow-Blue Lego - Intro to Java Programming
Udacity
6.9K views 10 likes 3 dislikes 23 Feb 2015100% match

What Does This Pseudocode Print? - Intro to Java Programming
Udacity
5.3K views 7 likes 1 dislikes 23 Feb 2015100% match

Hello, Udacity! - Intro to Java Programming
Udacity
19.3K views 39 likes 7 dislikes 23 Feb 2015100% match

Another Pseudocode Example - Intro to Java Programming
Udacity
10.2K views 13 likes 2 dislikes 23 Feb 2015100% match

Colors - Intro to Java Programming
Udacity
4.5K views 9 likes 1 dislikes 23 Feb 2015100% match

Downloading BlueJ - Intro to Java Programming
Udacity
12.3K views 8 likes 1 dislikes 23 Feb 2015100% match

Tidying Legos - Intro to Java Programming
Udacity
5.1K views 6 likes 0 dislikes 23 Feb 2015100% match

Introduction - Intro to Java Programming
Udacity
67.4K views 170 likes 8 dislikes 23 Feb 2015100% match

Our First Program - Intro to Java Programming
Udacity
9.4K views 31 likes 1 dislikes 23 Feb 2015100% match

Hello World Two Lines - Intro to Java Programming
Udacity
10K views 23 likes 1 dislikes 23 Feb 2015100% match

Move to the First Yellow-Blue Lego - Intro to Java Programming
Udacity
5.7K views 17 likes 16 dislikes 23 Feb 2015100% match

Hand Tracing - Intro to Java Programming
Udacity
35.4K views 203 likes 19 dislikes 16 Jul 2014100% match

Compile-Time and Runtime Errors 2 - Intro to Java Programming
Udacity
7.8K views 4 likes 0 dislikes 23 Feb 2015100% match

Text and Numbers - Intro to Java Programming
Udacity
7.3K views 15 likes 0 dislikes 23 Feb 201571% match

Downloading the Course Code - Intro to Java Programming
Udacity
10.1K views 10 likes 0 dislikes 23 Feb 201565% match

Downloading the Course Code - Intro to Java Programming
Udacity
17.6K views 20 likes 0 dislikes 23 Feb 201565% match

Instance Variable - Intro to Java Programming
Udacity
26.4K views 108 likes 10 dislikes 23 Feb 201527% match

Aprenda a fazer todos dribles do Dream League Soccer 2019
USBR
832K views 21.9K likes 881 dislikes 16 Dec 201726% match

Plan to Update Score
Udacity
32.3K views 9 likes 0 dislikes 08 Jul 201526% match

3 : Healthy Living Intro
Udacity
31.1K views 7 likes 0 dislikes 25 May 201526% match

NosTale - Ulepszam blue od 0 do +??
YumiYT
767 views 41 likes 5 dislikes 05 Aug 202025% match

Settings Privacy About Contact Donate