Please Explain this Constructor parameter type ?

[lakmal padmakumara]

 public DelaunayPoint (double... coords) {
        coordinates = new double[coords.length];
        System.arraycopy(coords, 0, coordinates, 0, coords.length);
    }

what is the meaning of this 3 dots ? This is a code which is related to my assignment .I'm trying to understand this !
Can we have this kind of parameters in the method also ?

what i noticed here was when I can call this constructor
DelaunayPoint d1=new DelaunayPoint (3,4,5);

or

DelaunayPoint d1=new DelaunayPoint (3,4);

So this 3 dots means you can send any number of arguments below 3 ? Is that so ?Confused ! Please Help Thanks !

[Vijitha Kumara]

lakmal padmakumara wrote:

 public DelaunayPoint (double... coords) {
        coordinates = new double[coords.length];
        System.arraycopy(coords, 0, coordinates, 0, coords.length);
    }

what is the meaning of this 3 dots ?

That denotes var-args, you can send any number of arguments to that method/constructor which matches the type of the argument defined.

[Rok Štelcer]

Hi,

Check following link for understanding:
http://java.sun.com/j2se/1.5.0/docs/guide/language/varargs.html


Regards,
Rok

[Salil Vverma]

... represents var-args operator. You can pass as many multiple values of the same type as you want or array of the same type. Kindly refer the below example for better understanding

   
public class Gened {

	public static void main(String argv[]) {
		Gened g = new Gened();
		g.doNumber(new int[] { 1, 2, 3, 4 });
		int x = 35;
		g.doNumber(x);
	}

	public void doNumber(int... dn) {
		for (int i : dn)
			System.out.println(i);
	}

}

 

The out put of the above code would be -1 2 3 4 35
I hope, this would clear all your doubts.

[lakmal padmakumara]

Hey Thanks !!! You People are really helpful !! It helped me a lot !!!