双链表创建、删除、添加节点-蒲公英云

双链表创建、删除、添加节点

#include<queue>
#include<iostream>
using namespace std;
// 有序链表
const int arrrlens = 9;
int arr[arrrlens] = { 0, 1, 2, 3, 5, 6, 7, 8, 9 };
class Node {
public:
    Node(int el = 0, Node* pNext = NULL, Node * pPre = NULL) {
        data = el;
        next = pNext;
        pre = pPre;
    }
    int data;
    Node* next, *pre;
};
class NodeList {
public:
public:
    NodeList() {
        head = new Node();
        tail = new Node();
    }
    ~NodeList() {
        delete head;
        delete tail;
    }
    int initList();
    int addElem(int);
    int delElem(int);
    int printList();
private:
    Node* head, *tail;
};
int NodeList::initList()
{
    Node* p = head;
    for (int i = 0; i < arrrlens; i++)
    {
        Node* node = new Node(arr[i]);
        p->next = node;
        node->pre = p;
        p = node;
    }
    return 0;
}
int NodeList::addElem(int node)
{
    Node* p = head, *cur = NULL;
    Node* newnode = new Node(node);
    // 越过头节点
    while (p->next != NULL && p->next->data <= node)
        p = p->next;
    if (p->next != NULL)
    {
        newnode->next = p->next;
        newnode->pre = p;
        p->next->pre = newnode;
        p->next = newnode;
        cout << "从中间插入节点..." << endl;
        return 1;
    }
    else {
        p->next = newnode;
        newnode->pre = p;
        cout << "从尾部插入节点..." << endl;
        return 1;
    }
    return 0;
}
int NodeList::delElem(int node)
{
    Node* p = head, * q, *cur;
    // 越过头节点
    p = p->next;
    while (p != NULL && p->data != node)
        p = p->next;
    if(p != NULL && p->next != NULL)
    { 
        p->pre->next = p->next;
        p->next->pre = p->pre;
        cout << "从中间删除节点..." << endl;
        return 1;
    }
    if (p != NULL && p->next == NULL)
    {
        p->pre->next = NULL;
        cout << "从尾部删除节点..." << endl;
        return 1;
    }
    cout << "该节点不存在..." << endl;
    return 0;
}
int NodeList::printList()
{
    Node* p = head;
    // 越过头节点
    p = p -> next;
    while (p != NULL)
    {
        cout << p->data << " ";
        p = p->next;
    }
    cout << endl;
    return 0;
}
int main()
{
    NodeList list;
    list.initList();
    list.printList();
    list.addElem(31);
    list.printList();
    list.addElem(2);
    list.printList();
    list.delElem(31);
    list.printList();
    list.delElem(3);
    list.printList();
    return 0;
}