如何在C语言中使用指针实现链表的插入和删除操作

#include
#include

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

// 插入节点到链表
void insertNode(Node** head, int value) {
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->data = value;
    newNode->next = NULL;

    if (*head == NULL) {
        *head = newNode;
    } else {
        Node* current = *head;
        while (current->next != NULL) {
            current = current->next;
        }
        current->next = newNode;
    }
}

// 删除指定数值的节点
void deleteNode(Node** head, int value) {
    if (*head == NULL) {
        return;
    }

    Node* current = *head;
    Node* prev = NULL;

    // 头节点就是要删除的节点
    if (current->data == value) {
        *head = current->next;
        free(current);
        return;
    }

    // 遍历链表，找到要删除的节点
    while (current != NULL && current->data != value) {
        prev = current;
        current = current->next;
    }

    // 删除节点
    if (current != NULL) {
        prev->next = current->next;
        free(current);
    }
}

int main() {
    Node* linkedList = NULL;

    insertNode(&linkedList, 10);
    insertNode(&linkedList, 20);
    insertNode(&linkedList, 30);

    printf("链表的初始状态：\n");
    Node* current = linkedList;
    while (current != NULL) {
        printf("%d ", current->data);
        current = current->next;
    }
    printf("\n");

    deleteNode(&linkedList, 20);

    printf("删除节点后的链表状态：\n");
    current = linkedList;
    while (current != NULL) {
        printf("%d ", current->data);
        current = current->next;
    }
    printf("\n");

    return 0;
}