小编Rob*_*ert的帖子

您好，我对 Java 很陌生，在为双向链表构建嵌套 Iterator 类时遇到了这个问题。我不确定如何编写一个public E next()方法来让它迭代双向链表。

任何帮助是极大的赞赏！

  private class DoubleListIterator implements Iterator<E> {
    // instance variable
    private Node current=head;
    private Node last;
    private int index=0;

    public boolean hasNext() {
      return index < N;
    }
    public E next() {
        if (!hasNext()) throw new NoSuchElementException();

    }
    public void remove() { throw new UnsupportedOperationException(); }
  }// end class ListIterator

嗨,我是Java的新手,在这段代码中,我想我不是在Main中正确创建Bag？请帮忙谢谢!

线程"main"中的异常java.lang.ClassCastException:[Ljava.lang.Object; 无法转换为[Ljava.lang.Comparable; atBag.(Bag.java:12)mid.Bag.main(Bag.java:91)

        public class Bag<T extends Comparable<T>> implements Iterable<T> {
      private int MAX_ITEMS = 10; // initial array size
      private int size;
      private T[] data;

      public Bag( ) {
        data = (T []) new Object[MAX_ITEMS];
        size = 0;
      }

      public void add(T newItem) {
        // check if it's full, then extend (array resizing)
        if (size == data.length) {
          T[ ] temp = (T [ ] ) new Object[data.length*2];
          for (int i = 0; i < size; ++i)
            temp[i] …