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Thread: Create an Array wich represent Classes

  1. #1
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    Default Create an Array wich represent Classes

    Not sure wheter to post it here or not, but I've got a question.
    I'm Trying to make the following:

    A Class called Point with the methods:
    SetPoint() //Sets pointx to 0 and pointy to 0
    SetPointNumber(int x, int y) //Set pointx to x and pointy to y
    Print() //Print pointx & pointy

    A Class called Shape with the methods:
    ShapeCreate() - This must create 3 points (an array) and set the point x & y to 0.

    I've got the following:
    class Point {
      int x, y;
      void Point() {
        x = 0;
        y = 0;
      }
      void Set(int x, int y) {
        this.x  = x;
        this.y  = y;
      }
      void Print() {
        System.out.println("x = " + x + "\nY = " + y);
      }
    }
     
    class Shape {
      void Shape() {
        Point Points[] = new Point[3];
     
        Point[1].Print();
        Point[2].Print();
        Point[3].Print();
     
      }
    }
     
    public class Practicum4VeelHoek {
      public static void main(String[] args) {
        Shape shape = new Shape();
     
      }
    }

    Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 3
    at practicum.pkg4.veelhoek.Veelhoek.Init(Practicum4Ve elHoek.java:29)
    at practicum.pkg4.veelhoek.Practicum4VeelHoek.main(Pr acticum4VeelHoek.java:50)
    Java Result: 1

    Does anybody know what I'm doing wrong
    Last edited by Sjaakie91; September 21st, 2011 at 06:41 AM.


  2. #2
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    Default Re: Create an Array wich represent Classes

    why
    class Shape {
      void Shape() {
        Point Points[] = new Point[3];
     
        Punten[1].Print();
        Punten[2].Print();
        Punten[3].Print();
     
      }
    }

    and not :
    class Shape {
      void Shape() {
        Point Points[] = new Point[3];
     
        Points[1].Print();
        Points[2].Print();
        Points[3].Print();
     
      }
    }

  3. #3
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    Default Re: Create an Array wich represent Classes

    Sorry in My java code it is OK, but on the Forum I translated it to English. I corrected my begin post.

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    Default Re: Create an Array wich represent Classes

    Array indexes start at zero. So an array of size 3 will have indexes 0, 1, and 2. Using 3 as an index is accessing the fourth element, which a length 3 array obviously doesn't have.

    Recommended reading: http://download.oracle.com/javase/tu...ts/arrays.html

    In the future, you might want to abide by the standard naming conventions. Methods and variables start with a lower-case letter, classes and constructors start with an upper-case letter. It might seem trivial, but it makes your code much harder to read if you don't follow the guidelines.
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