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Learning Java (Classes/Constructors

Name: Anonymous 2011-10-20 18:58

What do I need to look into to understand this better?
My professor gave an assignment to create a class called Circle in which I store the radius and diameter, using a constructor, then create a program that populates those variables using user input. I'm a bit confused because the book uses Rectangle as an example, and it seems that "Rectangle" and "box" are specifically part of java, whereas using "Circle" and "round" doesn't work for me.

I'm about to completely scratch what I have, copy the rectangle code, complile and run it to check it works, then try to customize it to work with a circle. Any advice would be much appreciated. Thanks. (Please don't just post code and do it for me.)

Name: Anonymous 2011-10-20 19:15

Alright, retyping their code, I realized that box and Rectangle are just arbitrary words they used to build their rectangle to call upon the method. Essentially Rectangle was referencing a previous code and box was a method of that code.

I used a similar method but now I'm getting the following error:

----------------------------------------------------------------
Circle.java:13: error: cannot find symbol
        return rad;
               ^
  symbol:   variable rad
  location: class Circle
Circle.java:17: error: cannot find symbol
        return dia;
               ^
  symbol:   variable dia
  location: class Circle
2 errors

Terminated with exit code 1.

Name: Anonymous 2011-10-20 19:43

Read SICP.

Name: Anonymous 2011-10-20 19:54

skip java... go directly to Scala

Name: Anonymous 2011-10-20 20:59




public class Circle
{
    public int radius;
    public int diameter;
   
    public int getRadius()
    {
        return radius;
    }
   
    public int getDiameter()
    {
        return diameter;
    }
}




public class CircleProg
{
    public static void main(String[]args)
    {
        Circle shit = new Circle();
        Scanner keyboard = new Scanner(System.in);
       
        System.out.println("Please enter a radius and a diameter.");
        int radiusInput = keyboard.nextInt();
        int diameterInput = keyboard.nextInt();
       
       
        shit.radius = radiusInput;
        shit.diameter = diameterInput;
       
       
        System.out.println("Returned radius is "+shit.getRadius());
        System.out.println("and returned diameter is "+shit.getDiameter());
       
    }
}


This what you are trying to do?

Name: Anonymous 2011-10-20 21:10

public class
public int
public int
public int
public int
public class
public static void

If it ain't Lisp, it's crap.

Name: Anonymous 2011-10-20 21:20

>>6
Lisp is shit.

Name: Anonymous 2011-10-20 21:28

>>7
you just didn't...

Name: Anonymous 2011-10-20 21:33


WARNING! >>8 IS ABOUT TO HAVE AN AUTISM SEIZURE!

Name: Anonymous 2011-10-20 22:23

>>5
I threw up in my mouth a little. It was delicious, so thank you.

Name: Anonymous 2011-10-20 22:26

>>5
>radius
>diameter
Nigger, what are you doing?

Name: Anonymous 2011-10-20 22:27

>>5
>radius
>diameter
Nigger, what are you doing?

Name: Anonymous 2011-10-20 22:30

double posting and quote fail
Nigger, what are you doing?

Name: Anonymous 2011-10-20 22:33

Welcome to Java!

interface ICircle {
    public void setRadius(double radius);
    public double getRadius();
    public void setDiameter(double diameter);
    public double getDiameter();
}

class Circle implements ICircle {
    private double radius;
    private double diameter;
   
    public void setRadius(double radius) {
        this.radius = radius;
    }
   
    public double getRadius() {
        return this.radius;
    }
   
    public void setDiameter(double diameter) {
        this.diameter = diameter;
    }
   
    public double getDiameter() {
        return this.diameter;
    }
}

class CircleFactory {
    public ICircle create() {
        return new Circle;
    }
}

public class CircleDriver {
    public static void main(String[] args) {
        ICircle circle = (new CircleFactory()).create();
        Scanner input = new Scanner(System.in);
       
        System.out.println("Please enter a radius and a diameter.");
        circle.setRadius(input.nextDouble());
        circle.setDiameter(input.nextDouble());
       
        System.out.println("Your radius is: " + circle.getRadius());
        System.out.println("Your diameter is: " + circle.getDiameter());
    }
}

Name: Anonymous 2011-10-20 22:49

>>14
>CircleFactory

what, is that really how java recommends?

Name: Anonymous 2011-10-20 23:21

>>15
what do you mean

Name: Anonymous 2011-10-20 23:23

>>15
not exactly, but it's pretty typical Java.

no reason Java HAS to be like this, it just usually is.

Name: Anonymous 2011-10-20 23:38

>>17
Does the JVM do some optimization to make that run well or is that just a giant waste of space?

Name: Anonymous 2011-10-21 0:33

>>14
>>17
That is indeed very accurate... Really reminds me of the code I'm working on at work.

Name: Anonymous 2011-10-21 7:05

GC is shit.

Name: Anonymous 2011-10-21 10:00

>>5

Public instance variable AND accessor methods? Radius AND diameter? (Hint: diameter = 2*radius)

Name: Anonymous 2011-10-21 10:03

>>21
#define diameter(anus) anus<<1

Name: Anonymous 2011-10-21 10:05

>>20
Fuck off and die, spammervoid.

Name: Anonymous 2011-10-21 10:07

>>5
public static final int pi = 3;
public final int getPi()
{
   return pi;
}


Thank me later.

Name: Anonymous 2011-10-21 10:19

>>24
Thanks!

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