java 循环链表 只有head指针

package link; class Node { public int num; public Node next; public Node(int num, Node next) {

this.num = num; this.next = next; } } public class CycleList { public Node head; public int size; public void insertHead(int element){ //在头结点的地方插入 if(size == 0){ head = new Node(element, null); head. next = head; }else { Node no = head; head = new Node(element, no); } size ++; } public void insert(int index, int element) { //插入元素 if (size == 0) { head = new Node(element, head); } else { if (index < 0) { index = 0; } if (index > size) { index = size; } Node no1 = head; for (int i = 0; i < index - 1; i++) { no1 = no1.next; } Node no2 = new Node(element, no1.next); no1.next = no2; } size++; } public void delete(int index) { if (index < 0) { index = 0; } // 删除函数

if (index > size) { index = size; } Node no3 = head; for (int i = 0; i < index - 1; i++) { no3 = no3.next; } no3.next = no3.next.next; size--; } public void select() { int sizelong = size; Node no4 = head; for (int i = 0; i < sizelong; i++) { System.out.print(no4.num); no4 = no4.next; } } public void update(int index, int element){ //更换index位置的内容 Node no7 = head; for(int i=0; i<index-1; i++){ no7 = no7.next; } no7.num = element; } public void sel(int index){ Node no8 = head; for(int i=0; i<index-1; i++){ no8 = no8.next; } System.out.println(no8.num); }