Question

Im having trouble implimenting the addAll method..

import java.util.Collection;

public interface Tree<E> extends Collection<E> {
/** Return true if the element is in the tree */
public boolean search(E e);

/** Insert element e into the binary tree
* Return true if the element is inserted successfully */
public boolean insert(E e);

/** Delete the specified element from the tree
* Return true if the element is deleted successfully */
public boolean delete(E e);
  
/** Get the number of elements in the tree */
public int getSize();
  
  
  
/** Inorder traversal from the root*/
public default void inorder() {
}

/** Postorder traversal from the root */
public default void postorder() {
}

/** Preorder traversal from the root */
public default void preorder() {
}
  
/** Return the height of this binary tree */
public int height(); // Left as exercise: implement in BST
]ff /** BreadthFirst traversal from the root */
public default void breadthFirstTreversal() {
// Left as an exercise: implement in BST
}
  
  
  
@Override /** Return true if the tree is empty */
public default boolean isEmpty() {
return this.size() == 0;
}

@Override
public default boolean contains(Object e) {
return search((E)e);
}
  
@Override
public default boolean add(E e) {
return insert(e);
}
  
@Override
public default boolean remove(Object e) {
return delete((E)e);
}
  
@Override
public default int size() {
return getSize();
}
  
@SuppressWarnings("unchecked")
@Override
public default boolean containsAll(Collection<?> c) {
// Left as an exercise

return true;
}

@SuppressWarnings("unchecked")
@Override
public default boolean addAll(Collection<? extends E> c) {
// Left as an exercise
  
return true;
}

@SuppressWarnings("unchecked")
@Override
public default boolean removeAll(Collection<?> c) {
// Left as an exercise
  
return true;
}

@SuppressWarnings("unchecked")
@Override
public default boolean retainAll(Collection<?> c) {
// Left as an exercise
  
return true;

}

@Override
public default Object[] toArray() {
// Left as an exercise
  
return temp;
}

@SuppressWarnings("unchecked")
@Override
public default <T> T[] toArray(T[] array) {
// Left as an exercise
  
return array;
}
  
}

Answer 1

Hi

The addAll() method code is -

public default boolean addAll(Collection<? extends E> c) {
// Left as an exercise
   boolean flag = true;
       for (E element: c) {
           flag &= add(element);
       }
  
return true;
}