Question

我需要帮助使这个toString方法传递到底部的测试。我目前正在收到错误（预期：＆lt; 0：20,1：[1] 0＆gt;但是＆lt; 0：20,1：[2] 0＆gt;）。 addFirst 100％工作，但我不确定这里有什么问题。

public class LList
{
  public Node head;
  private int i;
  private int size;

public void addFirst(int value)
{
    Node n = new Node();
    n.value = value;
    n.next = head;
    head = n;
}

public void removeFirst()
{
    if (head != null)
    {
        // commone case: there is at least one node
        head = head.next;
    }
    else
    {
        // no nodes
        throw new Banana();
    }
}

public int size()
{
    Node current = head;
    int count = 0;
    while(current != null)
    {
        count++;                    // keep count of nodes
        current = current.next;     // move to next node
    }
    return count;
}

public int get(int index)
{
    int count = 0;
    Node current = head;
    if (index < 0 || index >= size())
    {
        throw new Banana();
    }
    while(count != index)
    {
        count++;
        current = current.next;
    }
    return current.value;
}

   public String toString()
     {
    String s = "";
    Node current = head;
    //current = head;

    if (size() == 0)
    {
    return s;
    }
    else
    {
    s = s + "" + i + ":" + current.value;
    for (int i = 1; i < size(); i++)
    {
        s = s + ", " + i + ":" + current.value;
    }
    return s;
    }
}


public class Node
{
    public int value;
    public Node next;
}

@Test
public void testToString()
{
    LList a = new LList();
    assertEquals("", a.toString());
    a.addFirst(10);
    assertEquals("0:10", a.toString());
    a.addFirst(20);
    assertEquals("0:20, 1:10", a.toString());
    a.addFirst(30);
    assertEquals("0:30, 1:20, 2:10", a.toString());
}

Answer 1

你应该迭代（遍历）所有节点。

使用while循环，例如：

public String toString() {
    String s = "";
    Node current = head;
    // current = head;

    if (size() != 0) {
        int i = 0;
        s = s + "" + i + ":" + current.value;
        while(current.next != null) {
            i++;
            current = current.next;
            s = s + ", " + i + ":" + current.value;
        } 
    }
    return s;
}

我需要帮助制作一个必须通过某些测试的toString方法，Java

1 个答案: