单链表创建、删除、查找、插入之C语言实现

单链表是一种链式存储结构，由一个个结点构成，每个结点包含两个域：数据域和指针域。数据域用于存储数据，指针域用于指向下一个结点。以下是单链表的基本操作的C语言实现：

1.创建链表

typedef struct node {
    int data;
    struct node *next;
} Node;

Node *createList() {
    Node *head = NULL;
    Node *tail = NULL;
    int num;
    printf("请输入链表的数据，以-1结束：");
    scanf("%d", &num);
    while (num != -1) {
        Node *p = (Node*)malloc(sizeof(Node));
        p->data = num;
        p->next = NULL;
        if (head == NULL) {
            head = p;
            tail = p;
        } else {
            tail->next = p;
            tail = p;
        }
        scanf("%d", &num);
    }
    return head;
}

2.删除结点

Node *deleteNode(Node *head, int num) {
    Node *p = head;
    Node *prev = NULL;
    while (p != NULL && p->data != num) {
        prev = p;
        p = p->next;
    }
    if (p == NULL) {
        printf("链表中没有该结点\n");
        return head;
    }
    if (prev == NULL) {
        head = head->next;
    } else {
        prev->next = p->next;
    }
    free(p);
    return head;
}

3.查找结点

Node *searchNode(Node *head, int num) {
    Node *p = head;
    while (p != NULL && p->data != num) {
        p = p->next;
    }
    if (p == NULL) {
        printf("链表中没有该结点\n");
        return NULL;
    }
    return p;
}

4.插入结点

Node *insertNode(Node *head, int num, int index) {
    Node *p = (Node*)malloc(sizeof(Node));
    p->data = num;
    p->next = NULL;
    if (head == NULL) {
        if (index == 0) {
            return p;
        } else {
            printf("链表为空，不能插入结点\n");
            free(p);
            return NULL;
        }
    }
    if (index == 0) {
        p->next = head;
        return p;
    }
    Node *prev = head;
    Node *next = head->next;
    int i = 1;
    while (next != NULL && i != index) {
        prev = prev->next;
        next = next->next;
        i++;
    }
    if (i != index) {
        printf("插入位置超出链表长度\n");
        free(p);
        return head;
    }
    prev->next = p;
    p->next = next;
    return head;
}