java链表构建单链表空表H，插入abcdef，遍历

以下是Java代码：

class Node {
    char data;
    Node next;
    
    public Node(char data) {
        this.data = data;
        this.next = null;
    }
}

class LinkedList {
    Node head;
    
    public LinkedList() {
        this.head = null;
    }
    
    public void add(char data) {
        Node newNode = new Node(data);
        if (head == null) {
            head = newNode;
        } else {
            Node current = head;
            while (current.next != null) {
                current = current.next;
            }
            current.next = newNode;
        }
    }
    
    public void display() {
        Node current = head;
        while (current != null) {
            System.out.print(current.data + " ");
            current = current.next;
        }
    }
}

public class Main {
    public static void main(String[] args) {
        LinkedList list = new LinkedList();
        list.add('a');
        list.add('b');
        list.add('c');
        list.add('d');
        list.add('e');
        list.add('f');
        list.display();
    }
}

输出结果为：a b c d e f