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Index › Programming Questions & Help › Syntax Questions › LinkedList<primitive>
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LinkedList<primitive> ? (Read 1690 times)
miked3
LinkedList<primitive> ?
May 18th, 2010, 5:16pm  
Hello,

I'm trying to use a LinkedList to contain only integers.
In the interest of avoiding myIntger = (Integer)myList.get(i) every time I use .get, I'd like to declare the list as:
LinkedList<Integer> myList = new LinkedList();

Weird thing is, that line works just fine within setup(), but when I place it before setup() so that it can be globally accessed, it causes "unexpected token: void" when I try to run.

Heres code to test:
void setup(){
 LinkedList<Integer> myList = new LinkedList();
 for (int i = 0;i<10;i++){
   myList.add(i);
   println(myList.get(i));
 }
 int myInteger = myList.get(1)+myList.get(2);
 println("my integer is "+myInteger);
}
void draw(){
}
works fine but myList is local to setup() which is fairly useless.
Move the myList declaration to before setup() and it fails.  Ideas?

Thanks,
Mike
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ben_hem
Re: LinkedList<primitive> ?
Reply #1 - May 18th, 2010, 11:00pm  
Quote:
LinkedList myList = new LinkedList();

void setup(){
 for (int i = 0;i<10;i++){
   myList.add(i);
   println(myList.get(i));
 }
 int myInteger = (Integer)myList.get(1)+(Integer)myList.get(2);
 println("my integer is "+myInteger);
}
void draw(){
}



[Edit - whoops!  huzzah for reading comprehension]
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« Last Edit: May 19th, 2010, 7:36pm by ben_hem »  
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PhiLho 
Re: LinkedList<primitive> ?
Reply #2 - May 19th, 2010, 2:26am  
BenHem, OP wrote "In the interest of avoiding myIntger = (Integer)myList.get(i) every time I use .get, " Wink

miked3, you must write:
LinkedList<Integer> myList = new LinkedList<Integer>();
ie. you must repeat the type in the instantiation. Yes, that's heavy...
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miked3
Re: LinkedList<primitive> ?
Reply #3 - May 19th, 2010, 10:08am  
LinkedList<Integer> myList = new LinkedList<Integer>();

void setup(){
}

gives "unexpected token: <"
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miked3
Re: LinkedList<primitive> ?
Reply #4 - May 19th, 2010, 10:17am  
Also, is using BenHem's suggested code any less efficient than declaring the whole list as <Integer>?

Thanks for the replies.
-mike
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Smitty
Re: LinkedList<primitive> ?
Reply #5 - May 19th, 2010, 11:54am  
miked3 wrote on May 19th, 2010, 10:08am:
LinkedList<Integer> myList = new LinkedList<Integer>();

void setup(){
}

gives "unexpected token: <"

I think what's happening is that Processing tries to replace every occurence of LinkedList with LinkedList<Object> before compiling. So, when you type:
Code:

LinkedList<Integer>

the compiler sees:
Code:

LinkedList<Object><Integer>

which generates the error you're getting.

One way to make it a little more convenient would be to write a wrapper method for myList.get() that does the cast for you:
Code:
Integer listGet(int i) {
  return (Integer) myList.get(i);
}


Other than that, the only way I can think of to get around this is to switch from the PDE to Eclipse.
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PhiLho 
Re: LinkedList<primitive> ?
Reply #6 - May 20th, 2010, 1:02am  
miked3 wrote on May 19th, 2010, 10:08am:
LinkedList<Integer> myList = new LinkedList<Integer>();

void setup(){
}

gives "unexpected token: <"

It works for me...
Then again, I use Processing 0184, which I assumed you were using.
If you use Processing 1.1, you don't have access to this syntax.
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