用c语言实现双向链表的基本操作

双向链表的基本操作包括创建、插入、删除和遍历等操作。以下是用C语言实现双向链表的基本操作的示例代码：

#include <stdio.h>
#include <stdlib.h>

struct Node {
    int data;
    struct Node* prev;
    struct Node* next;
};

struct Node* createNode(int data) {
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    newNode->data = data;
    newNode->prev = NULL;
    newNode->next = NULL;
    return newNode;
}

void insertAtBeginning(struct Node** headRef, int data) {
    struct Node* newNode = createNode(data);
    newNode->next = *headRef;
    if (*headRef != NULL) {
        (*headRef)->prev = newNode;
    }
    *headRef = newNode;
}

void insertAtEnd(struct Node** headRef, int data) {
    struct Node* newNode = createNode(data);
    struct Node* lastNode = *headRef;
    if (*headRef == NULL) {
        *headRef = newNode;
        return;
    }
    while (lastNode->next != NULL) {
        lastNode = lastNode->next;
    }
    lastNode->next = newNode;
    newNode->prev = lastNode;
}

void deleteNode(struct Node** headRef, int key) {
    struct Node* nodeToDelete = *headRef;
    if (nodeToDelete != NULL && nodeToDelete->data == key) {
        *headRef = nodeToDelete->next;
        if (*headRef != NULL) {
            (*headRef)->prev = NULL;
        }
        free(nodeToDelete);
        return;
    }
    while (nodeToDelete != NULL && nodeToDelete->data != key) {
        nodeToDelete = nodeToDelete->next;
    }
    if (nodeToDelete == NULL) {
        printf("Node with key %d not found\n", key);
        return;
    }
    nodeToDelete->prev->next = nodeToDelete->next;
    if (nodeToDelete->next != NULL) {
        nodeToDelete->next->prev = nodeToDelete->prev;
    }
    free(nodeToDelete);
}

void printList(struct Node* node) {
    while (node != NULL) {
        printf("%d ", node->data);
        node = node->next;
    }
    printf("\n");
}

int main() {
    struct Node* head = NULL;
    insertAtEnd(&head, 1);
    insertAtEnd(&head, 2);
    insertAtBeginning(&head, 3);
    printList(head);
    deleteNode(&head, 1);
    printList(head);
    return 0;
}

在上述代码中，我们定义了一个`Node`结构体来表示双向链表中的节点。`createNode`函数用于创建一个新的节点，`insertAtBeginning`函数用于在链表头部插入一个节点，`insertAtEnd`函数用于在链表尾部插入一个节点，`deleteNode`函数用于删除指定数据的节点，`printList`函数用于遍历并打印链表中的所有数据。在`main`函数中，我们创建了一个空链表，然后依次执行了插入操作和删除操作，并打印了最终的链表。