双链表的代码实现：

主要是双链表的常用操作，末尾有目录，可以收藏

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <iostream>

typedef struct DNode {
    int data;
    struct DNode* prior;
    struct DNode* next;
}DNode, *DlinkList;

void initList(DlinkList &d) {
    d = (DlinkList)malloc(sizeof(DNode));
    d->next = NULL;
    d->prior = NULL;
}

void HeadInsert(DlinkList &d, int x) {
    DlinkList s;
    if (d->next == NULL) {
        s = (DlinkList)malloc(sizeof(DNode));
        s->next = NULL;
        s->prior = d;
        d->next = s;
        s->data = x;
    }
    else
    {
        s = (DlinkList)malloc(sizeof(DNode));
        s->next = d->next;
        d->next->prior = s;
        s->prior = d;
        d->next = s;
        s->data = x;
    }
}

int getLength(DlinkList d) {
    int len = 0;
    DlinkList s = d->next;
    while (s != NULL){
        len++;
        s = s->next;

    }
    return len;
}

bool empty(DlinkList d) {
    if (d->next == NULL) {
        return true;
    }
    else
    {
        return false;
    }
}

DlinkList getNode(DlinkList d, int index) {
    if (!empty(d)) {
        int len = getLength(d);
        if (index < 1 || index > len) {
            printf("查找越界\n");
            return NULL;
        }
        else
        {
            int j = 1;
            DlinkList s = d->next;
            while (j < index) {
                s = s->next;
                j++;
            }
            return s;
        }
    }
    else
    {
        printf("链表为空\n");
        return NULL;
    }
}

void tailList(DlinkList &d, int x) {
    DlinkList s;
    if (d->next == NULL) {
        s = (DlinkList)malloc(sizeof(DNode));
        s->next = NULL;
        s->prior = d;
        d->next = s;
        s->data = x;
    }
    else
    {
        int len = getLength(d);
        DlinkList t = getNode(d,len);
        s = (DlinkList)malloc(sizeof(DNode));
        s->next = NULL;
        s->prior = t;
        t->next = s;
        s->data = x;
    }
}

void showList(DlinkList d) {
    DlinkList s = d->next;
    while (s != NULL){
        printf("%d\n", s->data);
        s = s->next;
    }
}

//按位删除
void deleteNodeByIndex(DlinkList &d, int index) {
    int len = getLength(d);
    if (empty(d)) {
        printf("链表为空\n");
        return;
    }
    if (index < 0 || index > len) {
        printf("参数越界\n");
        return;
    }

    if (index == len) {
        DlinkList p = getNode(d, index - 1);
        DlinkList q = getNode(d, index);
        p->next = NULL;
        q->prior = NULL;
        free(q);
    }
    else if(index == 1)
    {
        DlinkList q = getNode(d, index);
        d->next = q->next;
        q->next->prior = d;
        free(q);
    }
    else
    {
        DlinkList p = getNode(d, index - 1);
        DlinkList q = getNode(d, index);
        p->next = q->next;
        q->next->prior = p;
        free(q);
    }
}

int main() {
    DlinkList d;
    initList(d);
    //HeadInsert(d, 1);
    //HeadInsert(d, 2);
    //HeadInsert(d, 3);
    //HeadInsert(d, 4);
    tailList(d, 1);
    tailList(d, 2);
    tailList(d, 3);
    tailList(d, 4);
    showList(d);
    deleteNodeByIndex(d, 1);
    deleteNodeByIndex(d, 3);
    showList(d);
}

查看考研数据结构目录：

https://www.acwing.com/file_system/file/content/whole/index/content/5394132/