CODEWITHSUNDEEP
java
user1920811
user1920811

Reputation:

Can anyone explaint the output?

I know the output is four one three two. Can any one explain how? Since there are five items, but only four are printed.

TreeSet map = new TreeSet();

map.add("one");
map.add("two");
map.add("three");
map.add("four");
map.add("one");
Iterator it = map.iterator();
while (it.hasNext() ) 
{
    System.out.print( it.next() + " " );
}

Upvotes: 1

Views: 387

Answers (3)

amicngh
amicngh

Reputation: 7899

Set's doesn't allow duplicates .Where you are adding duplicate again like 'one' it is not being added .

TreeSet map = new TreeSet();

    System.out.println(map.add("one"));
    map.add("two");
    map.add("three");
    map.add("four");
    System.out.println(map.add("one"));

    Iterator it = map.iterator();
    while (it.hasNext() )
    {
        System.out.print( it.next() + " " );
    }

Result:

true
false

Second element didn't get added to the set .

While adding it checks if(e==null ? e2==null : e.equals(e2)) is true then only add element to Set otherwise don't.

Upvotes: 1

Byter
Byter

Reputation: 1132

TreeSet is an Implementation of Set Interface

And Set always contain only unique elements

So even though you have put 5 elements the TreeSet actually contains only 4 since "one" is repeated twice.

Upvotes: 0

user1920811
user1920811

Reputation:

TreeSet does not allow duplicate entries. When it is accessed it will return elements in natural order (alphabetical order).

Refer: http://docs.oracle.com/javase/6/docs/api/java/util/TreeSet.html

Upvotes: 6

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