LinkedList（）实现类

Question

import java.util.List;

public class LinkedList {

private List ls;

LinkedList() {

this.ls = new LinkedList();    //为什么这句会报错呢？LinkedList不也是List的实现类吗？

}

}

Answer 1

你要 import java.util.LinkedList; ll.addFirst() 这个要写参数：ll.addFirst(new News(2,"a","s"));

Answer 2

没导包!

Answer 3

好不容易弄好了 为什么带不出addFirst(),removeFirst()这些方法？import java.util.LinkedList;import java.util.List;public class LinkedListTest { private List ll; LinkedListTest() { this.ll = new LinkedList(); } void add() { ll.add(new News(1,"u","k")); ll.add(new News(2,"m","z")); ll.add(new News(2,"a","s")); ll.addFirst()   //这句编译报错 }}