calling variables from a class to a subclass

Asked Sep 17 '14 at 00:47

Active May 13 '15 at 20:09

Viewed 54 times

I am trying to set the endpoints of a trapezoid, square, etc. For example: TRX (top right x) is 2 and TRY (top right y) is 2, so the top right point is at (2,2). I am wondering how to use the variables in the subclass with the given hierarchy:

public class Quadrilateral {
    private int TRX, TLX, BRX, BLX;
    private int TRY, TLY, BRY, BLY;

    public static void main(String[] args) {
    }
}

class Trapezoid extends Quadrilateral {
}

class Square extends Quadrilateral {
}

edited May 13 '15 at 20:09

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asked Sep 17 '14 at 00:47

user1914650

2

Use getters and setters? – chrylis -cautiouslyoptimistic- Sep 17 '14 at 00:56
3

You cannot access a `private` attribute in a subclass. You'll either need to make it `protected` or add `getXYZ()` methods. That said, working through a Java tutorial would probably be useful. – 5gon12eder Sep 17 '14 at 00:56
Demo? Just wondering what the syntax would look like – user1914650 Sep 17 '14 at 00:57
@chrylis Using setters would be fatal in this example. In contrary, the attributes should be made `final`. How else could a `Square` ensure it's class invariants? – 5gon12eder Sep 17 '14 at 00:58
can you say that a little for "dumbed down"? im like 2 weeks into this. – user1914650 Sep 17 '14 at 01:00
@user1914650 This is a trivial exercise and sounds very much like homework. I don't know how to give you a demo without doing your homework. Maybe work through a tutorial like I've suggested. – 5gon12eder Sep 17 '14 at 01:00
Well of course its Homework. I'm just looking for a start is all. – user1914650 Sep 17 '14 at 01:04
like what is a getXYZ()? – user1914650 Sep 17 '14 at 01:06
It's a `getter` method for XYZ class variable. – PM 77-1 Sep 17 '14 at 01:07
2

Try [`Inheritance Tutorial`](http://docs.oracle.com/javase/tutorial/java/IandI/subclasses.html). If it's too difficult then start with very basic stuff. – PM 77-1 Sep 17 '14 at 01:09
Also read http://stackoverflow.com/q/215497/2654518 – ericbn Sep 17 '14 at 01:10

calling variables from a class to a subclass

0 Answers0