treeset question

[geeta vemula]

I got this from K and B master exam (learnkey)

private Set<Integer> numbers=new TreeSet<Integer>();

public Nmbers(int... nums) {
for(int n: nums)
numbers.add(n);
}

public Numbers negate() {
Numbers negatives=new Numbers(); //Line 1
for(int n: numbers)
negatives.numbers.add(-n);
return negatives;
}

public void show() {
for(int n : numbers)
System.out.println(n+"");
}
public static void main(String[] args)
{
new Numbers(1,3,-5).negate().show();
}
}

Answer is : -3 -1 5

In this at line 1 it is trying to call Numbers negatives=new Numbers();
(no arg constructor) then won't it give compiler error?

[Preethi Dev]

I am also surprised to this question,because compiler wont create no-arg constructor if we created one.In this case how it is possible (numbers n=new numbers() invoking show()?

Thanks
preetha

[Himanshu Gupta]

Where is the Numbers Class?

  public [B]Nmbers[/B](int... nums) {
for(int n: nums)
numbers.add(n);
}
 
[B]Numbers [/B]negatives=new Numbers(); //Line 1
 
  

If they are same then it is legal to not pass any arguments if your constructor is taking var-args. You may or may not pass any number of arguments.
[ December 20, 2008: Message edited by: Himanshu Gupta ]

[Preethi Dev]

Ya , i got it. it can take zero as argument.so it i possible to create no-arg constructor.am i right?

Thanks
Preetha

[Himanshu Gupta]

YES you are right.

[geeta vemula]

yes i got it..

Thanks,
Geeta Vemula