实现双端链接列表时"Cannot find this symbol"错误

Question

class Link {
    public int data;
    public Link next;
    public Link(int d) {
        data = d;
    }
    public void displayLink() {
        System.out.println(data + "");
    }
}
class firstlastList {
    private Link first;
    private Link last;
    public firstlastList() {
        first = null;
        last = null;
    }
    public boolean isEmpty() {
        return first == null;
    }
    public void insertfirst(int dd) {
        Link newLink = new Link(dd);
        if (isEmpty())
            last = newLink;
        newLink.next = first;
        first = newLink;
    }
    public void insertLast(int dd) {
        Link newLink = new Link(dd);
        if (isEmpty())
            first = newLink;
        else
            last.next = newLink;
        last = newLink;
    }
    public long deletefirst() {
        long temp = first.data;
        if (first.next == null)
            last = null;
        first = first.next;
        return temp;
    }
    public void displayList() {
        System.out.println("List(first-->last)");
        Link current = first;
        while (current != null) {
            current.displayLink();
            current = current.next;
        }
        System.out.println("");
    }
}
class FirstLastApp {
    public static void main(String args[]) {
        FirstLastApp theList = new FirstLastApp();
        theList.insertfirst(10);
        theList.insertfirst(98);
        theList.insertfirst(112);
        theList.insertLast(123);
        theList.insertLast(75);
        theList.insertLast(12);
        theList.displayList();
        theList.deletefirst();
        theList.deletefirst();
        theList.displayList();
    }
}

Answer 1

这一行似乎是一个错误(打字错误?):

FirstLastApp theList = new FirstLastApp();

请尝试更改为:

firstlastList theList = new firstlastList();