Chapter 18: Problem 16

What element does the remove method (in the Iterator interface) remove?

Short Answer

Expert verified

Answer: The remove() method in the Iterator interface removes the last element returned by the iterator's next() method. It can be called only once per call to the next() method, and calling it twice in a row without calling next() in between will result in an IllegalStateException.

Step by step solution

Understanding the Iterator Interface

An Iterator is an object that allows us to traverse through a collection (such as a list or a set) and manipulate the elements of that collection. The Iterator interface has three primary methods: hasNext(), next(), and remove().

The remove() Method

The remove() method removes an element from the collection that the iterator is traversing. Specifically, it removes the last element that was returned by the iterator’s next() method.

When to Call the remove() Method

It is important to note that the remove() method can only be called once per call to the next() method. This means that, before calling remove() to remove an element from the collection, the next() method must be called. Calling remove() twice in a row without calling next() in between will result in an IllegalStateException.

Using the remove() Method

Here's a step-by-step guide to using the remove() method in an Iterator: 1. Create an iterator for the collection you want to traverse, e.g., `Iterator iterator = list.iterator();` 2. Use the hasNext() method to check if there is a next element in the collection: `while (iterator.hasNext()) { ... }`. 3. Call the next() method to retrieve the next element from the collection: `String element = iterator.next();`. 4. If you want to remove the element just retrieved, call the remove() method: `iterator.remove();`. Keep in mind that the remove() method removes the last element returned by the next() method, and it can only be called once per call to next().

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What element does the remove method (in the Iterator interface) remove?

Short Answer

Step by step solution

Understanding the Iterator Interface

The remove() Method

When to Call the remove() Method

Using the remove() Method

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