LinkList的增删查改

package com.lanyuan.log;

public class Test1 {

    private TNode head;

    private int size;

    private TNode last;

    public int size() {
        return this.size + 1;
    }

    public Test1() {
        head = last = null;
    }

    public void add(int val) {
        TNode node = new TNode(val);
        if (head == null) {
            head = last = node;
            last.next = head;
        } else {
            last.next = node;
            last = last.next;
            last.next = head;
        }
        size++;
    }

    public int deleteLast() {
        if (head == null) {
            throw new RuntimeException("it's not allow");
        }
        TNode node = head.next;
        int val = last.val;
        for (int i = 0; node != null && node.next != last; i++) {
            node = node.next;
        }
        size--;
        last.next = node;
        last = last.next;
        last.next = head;
        return val;
    }

    public boolean updaetLast(int val) {
        if (head == null) {
            throw new RuntimeException("it's not allow");
        }
        last.val = val;
        return last != null;
    }

    public int findLast() {
        if (head == null) {
            throw new RuntimeException("it's not allow");
        }
        return last.val;

    }

    public String toString() {
        if (head == null) {
            return "TLink[]";
        }

        StringBuilder sb = new StringBuilder();
        TNode node = head.next;
        sb.append("TLink[" + head.val);
        for (int i = 0; i < size && node != head; i++) {
            sb.append("," + node.val);
            node = node.next;
        }
        sb.append("]");
        return sb.toString();
    }
}

class TNode {
    // 为了简单这里存储int类型数据,可以改成泛型
    public int val;
    public TNode next;

    public TNode() {
        super();
    }

    public TNode(int val) {
        this.val = val;
    }

}