package ch16;
import java.util.Iterator;
/**
 * Created by 春旺 on 2017/10/18.
 */
public interface BinaryTree<T> extends Iterable<T>
{
    // Returns the element stored in the root of the tree.
    public T getRootElement();
    // Returns the left subtree of the root.
    public BinaryTree<T> getLeft();
    // Returns the right subtree of the root.
    public BinaryTree<T> getRight();
    // Returns true if the binary tree contains an element that
// matches the specified element and false otherwise.
    public boolean contains (T target) throws ElementNotFoundException;
    // Returns a reference to the element in the tree matching
// the specified target.
    public T find (T target) throws ElementNotFoundException;
    // Returns true if the binary tree contains no elements, and
// false otherwise.
    public boolean isEmpty();
    // Returns the number of elements in this binary tree.
    public int size();
    // Returns the string representation of the binary tree.
    public String toString();
    // Returns a preorder traversal on the binary tree.
    public Iterator<T> preorder();
    // Returns an inorder traversal on the binary tree.
    public Iterator<T> inorder();
    // Returns a postorder traversal on the binary tree.
    public Iterator<T> postorder();
    // Performs a level-order traversal on the binary tree.
    public Iterator<T> levelorder();
}