Back to General and Gameplay Programming

[java] Objects in Java - a beginner

cordel · 2009-01-09T02:03:53

Hello everyone . I have a class called "ShapeContainer" and I need to build its Constructor. Its declaration : public ShapeContainer() // Constructs a container which holds no shapes each cell is type Point ,when Point is an object : public Point () { // Constructs a point in (0,0) xval=0; yval=0; } so I wrote : public class ShapeContainer { public static final int INIT_SIZE=10; Point[] shape_arr; public ShapeContainer() { // Constructs a container // with no cells shape_arr=new Point[INIT_SIZE]; } but I need to initialize shape_arr with null , how do I do it ? thanx in advance. }

General and Gameplay Programming Programming

Started by cordel January 08, 2009 03:59 AM

11 comments, last by cordel 15 years, 3 months ago

cordel

122

Author

January 08, 2009 06:39 AM

okay I'll be more specific.
Like I said before I have a 10 cell array , and each cell has 2 fields - one for Triangles and the other for Rectangles.
A rectangle defined by two points (two x,y) and triangle by three points (three x,y).

how can I define an array that each cell has two fields ,the 'x' would be of type Triangle ,the 'y' - type Rectangle.

For now I've seperated the problem into 2 different arrays ,

Quote:
public ShapeContainer() {
arrrec=new Rectangle[INIT_SIZE];
arrtri=new Triangle[INIT_SIZE];
}

I want to use one array of [10] when the 1st field (x) would be of type Triangle,and the 2nd (y) of type Rectangle.is it possible ? thank you

OrangyTang

1,298

January 08, 2009 07:43 AM

Quote:Original post by cordel
I want to use one array of [10] when the 1st field (x) would be of type Triangle,and the 2nd (y) of type Rectangle.is it possible ? thank you

The best way would be to have an array of a new class, which had both a triangle and a rectangle as a member. Something like:

public class Pair{  public Rectangle rect;  public Triangle tri;}public class ShapeContainer{  private Pair[] allPairs; // Array of 'Pair' objects  public ShapeContainer()  {    allPairs = new Pair[INIT_SIZE]; // Create empty array of Pair objects    for (int i=0; i<allPairs.length; i++)    {      allPairs = new Pair(); // Create a Pair object in each slot of the array    }  }  public void add(Rectangle r, Triangle t)  {    for (int i=0; i<allPairs.length; i++)    {      // Is this slot used?      if (allPairs.rect == null && allPairs.tri == null)      {        allPairs.rect = new Rectangle(r);        allPairs.tri = new Triangle(t);        break;      }    }  }}

Although instead of having a fixed size array and having used and unused slots you may want to consider using ArrayList which is a resizable array and would make your code simpler.

Also 'Pair' is a fairly rubbish name - again you've been very vauge and it's not obvious what exactly you're trying to do. There's probably a much better name you could pick depending on what the rectangle/triangle pair is supposed to represent.

[size="1"][[size="1"]TriangularPixels.com[size="1"]] [[size="1"]Rescue Squad[size="1"]] [[size="1"]Snowman Village[size="1"]] [[size="1"]Growth Spurt[size="1"]]

cordel

122

Author

January 09, 2009 02:03 AM

OrangyTang ,thank you very much (and also to the rest of you guys)
I'll check both ways and see which one is more preferable.

[java] Objects in Java - a beginner

This topic is closed to new replies.

Popular Topics

Recommended Tutorials

[java] Objects in Java - a beginner

This topic is closed to new replies.

Popular Topics

Recommended Tutorials

Reticulating splines