数据结构：带头节点单循环链表类的实现（C++）（考研）

#include <bits/stdc++.h>
using namespace std;



class LinkedCircleList {
private:
	struct node {
		int val;
		node *next;
		
		node() {}
		node(int x, node *next) {
			this->val = x;
			this->next = next;
		} 
	};	
	
	int size;
	node *head;
	
	
public:
	LinkedCircleList() {
		this->size = 0;
		head = new node;
		head->next = head;
	}
	
	~LinkedCircleList() {
		while (head!=head->next) {
			delTail();
		}
		delete head; 
	}
	
	
	
	void insert(int index, int x) {
		if (index<0 || index>size) {
			cout << "the index is invalid!" << endl;
			return;
		}
		
		node *p = head;
		for (int i=0; i<index; ++i) p = p->next;
		node *q = new node(x, p->next);
		p->next = q;
		size ++;
	}
	void insertHead(int x) {insert(0, x);}
	void insertTail(int x) {insert(size, x);}
	
	int del(int index) {
		if (index<0 || index>=size) {
			cout << "the index is invalid!" << endl;
			return -1;
		} 
		
		if (head->next == head) {
			cout << "the LinkedCircleList is null！" << endl;
			return -1; 
		}
		
		node *p = head;
		for (int i=0; i<index; ++i) p = p->next;
		node *del = p->next;
		p->next = del->next;
		int res = del->val;
		delete del;
		size --;
		return res;
	}
	int delTail() {del(size-1);}
	int delHead() {del(0);}
	
	int get(int index) {
		if (index < 0 || index>=size) {
		 	cout << "the index is invalid!" << endl;
			return -1; 
		}
		 
		if (head->next == head) {
			cout << "the LinkedCircleList is null！" << endl;
			return -1; 
		}
		
		node *p = head->next;
		for (int i=0; i<index; ++i) p = p->next;
		return p->val;
	}
	int getHead() {get(0);}
	int getTail() {get(size-1);}
	
	void show() {
		node *p = head->next;
		while (p!=head) {
			cout << p->val << " ";
			p = p->next;
		}
		cout << endl;
	}
	
	bool isEmpty() {return head->next == head;}
};
int main() {
	int a[] = {1};
	int n = sizeof(a)/sizeof(int);
	LinkedCircleList list = LinkedCircleList();
	for (int i=0; i<n; ++i) list.insertTail(a[i]);
	list.show(); 
	cout << list.getHead() << endl;
	cout << list.getTail() << endl;
	return 0;
}