链表基本操作

链表基本操作

（临时抱佛脚的笔记）

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

// 定义链表节点结构
struct Node {
    int data;
    struct Node *next;
};

// 创建新节点
struct Node* createNode(int data) {
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    if (newNode == NULL) {
        printf("内存分配失败\n");
        exit(1);
    }
    newNode->data = data;
    newNode->next = NULL;
    return newNode;
}

// 在链表头部插入节点
struct Node* insertAtBeginning(struct Node *head, int data) {
    struct Node *newNode = createNode(data);
    newNode->next = head;
    return newNode;
}

// 在链表尾部插入节点
void insertAtEnd(struct Node *head, int data) {
    struct Node *newNode = createNode(data);
    struct Node *temp = head;
    while (temp->next != NULL) {
        temp = temp->next;
    }
    temp->next = newNode;
}

// 删除第一个值为 data 的节点
struct Node* deleteNode(struct Node *head, int data) {
    struct Node *current = head;
    struct Node *prev = NULL;

    // 查找要删除的节点并记录其前一个节点
    while (current != NULL && current->data != data) {
        prev = current;
        current = current->next;
    }

    // 若找到要删除的节点，则删除它
    if (current != NULL) {
        if (prev == NULL) {
            head = current->next; // 删除头节点
        } else {
            prev->next = current->next; // 删除中间或尾节点
        }
        free(current);
    }

    return head;
}

// 打印链表
void printList(struct Node *head) {
    struct Node *temp = head;
    while (temp != NULL) {
        printf("%d ", temp->data);
        temp = temp->next;
    }
    printf("\n");
}

// 释放链表节点
void freeList(struct Node *head) {
    struct Node *temp;
    while (head != NULL) {
        temp = head;
        head = head->next;
        free(temp);
    }
}

int main() {
    struct Node *head = NULL; // 初始化链表头节点

    // 在链表头部插入节点
    head = insertAtBeginning(head, 10);
    head = insertAtBeginning(head, 20);
    head = insertAtBeginning(head, 30);

    // 在链表尾部插入节点
    insertAtEnd(head, 40);
    insertAtEnd(head, 50);

    printf("链表内容：\n");
    printList(head);

    // 删除节点
    head = deleteNode(head, 20);

    printf("删除后的链表内容：\n");
    printList(head);

    // 释放链表节点内存
    freeList(head);

    return 0;
}