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PTR (Read 355 times)
JScriptChan
PTR
Mar 16th, 2009, 8:51am  
Hello ladies & gentlemen,how can I make use of pointers in processing IDE just like we do in C++ or so?Thank you for your answers.
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more joy,more practice
JScriptChan 568009148  
PhiLho 
Re: PTR
Reply #1 - Mar 16th, 2009, 10:36am  
I think you ask the wrong question.
You should explain instead what you want/need to do, and we will explain how to do it in Java (Processing).

In short, there are no pointers in Java, the nearest thing is object references.
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WWW  
JScriptChan
Re: PTR
Reply #2 - Mar 16th, 2009, 1:29pm  
I'm sorry to cause you such trouble,but I mean to make a tree-like structure of pictures,say,to make a tree whose nodes are pictures.How to?Thank you for your attention.
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more joy,more practice
JScriptChan 568009148  
JohnG
Re: PTR
Reply #3 - Mar 16th, 2009, 1:39pm  
You can do it quite easily. You pass objects by reference by default, and so you can put the references in an array or assign them to local names etc easily.

Code:
class node
{
  node[] children;
  PImage img;
  node(PImage _img)
  {
    img=_img;
  }
  
  void addChild(node n)
  {
    children=(node[])append(n,children);
  }
}
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JScriptChan
Thank you,but a few problems remained
Reply #4 - Mar 17th, 2009, 4:38am  
I made the test below:
node n1;
int i;
node nodenew;

void setup()
{
 size(200,200);
 n1=new node(1);
}

void draw()
{

}

void mouseClicked()
{
 nodenew=new node(2);
 n1.addchild(nodenew);
 n1.pt();

}

class node
{
 node[] children;
 int count;
 node(int _count)
 {
   count=_count;
 }
 
 void addchild(node n)
 {
   children=(node[])append(n,children);
 }
 void pt()
 {
   println(this.count);
 }
}

then I have error messages:
Exception in thread "Animation Thread" java.lang.IllegalArgumentException: Argument is not an array
at java.lang.reflect.Array.getLength(Native Method)
at processing.core.PApplet.append(PApplet.java:4715)
at picnude$node.addchild(picnude.java:50)
at picnude.mouseClicked(picnude.java:35)
at processing.core.PApplet.handleMouseEvent(PApplet.java:1609)
at processing.core.PApplet.dequeueMouseEvents(PApplet.java:1539)
at processing.core.PApplet.handleDraw(PApplet.java:1434)
at processing.core.PApplet.run(PApplet.java:1328)
at java.lang.Thread.run(Thread.java:619)

It seems confusing,please help!Thank you again!
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more joy,more practice
JScriptChan 568009148  
JohnG
Re: PTR
Reply #5 - Mar 17th, 2009, 10:07am  
Oops, I may have got the arguments to append the wrong way round, try (node[])append(children,n);
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