5.以C结构体或C++的“类”代替“第2章中复杂数据类型”，实现“链式线性表”，编写下面6个接口函数：CreateList、ListPrint、GetElem、ListLength、ListInsert、ListDelete

C结构体定义：

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

typedef struct List {
    Node *head;
    int length;
} List;

1. CreateList：创建链表

void CreateList(List *list)
{
    Node *node = NULL;
    Node *tail = NULL;
    int data;

    // 初始化链表
    list->head = NULL;
    list->length = 0;

    printf("输入链表数据，以-1结束：");
    while (1) {
        scanf("%d", &data);
        if (data == -1) {
            break;
        }

        node = (Node *)malloc(sizeof(Node));
        node->data = data;
        node->next = NULL;

        if (list->head == NULL) {
            list->head = node;
            tail = node;
        } else {
            tail->next = node;
            tail = node;
        }

        list->length++;
    }
}

2. ListPrint：打印链表

void ListPrint(List *list)
{
    Node *node = list->head;

    printf("链表数据：");
    while (node != NULL) {
        printf("%d ", node->data);
        node = node->next;
    }
    printf("\n");
}

3. GetElem：获取指定位置的节点数据

int GetElem(List *list, int pos, int *data)
{
    Node *node = list->head;
    int i = 1;

    if (pos < 1 || pos > list->length) {
        return 0;
    }

    while (node != NULL) {
        if (i == pos) {
            *data = node->data;
            return 1;
        }
        i++;
        node = node->next;
    }

    return 0;
}

4. ListLength：获取链表长度

int ListLength(List *list)
{
    return list->length;
}

5. ListInsert：在指定位置插入节点

int ListInsert(List *list, int pos, int data)
{
    Node *node = NULL;
    Node *prev = NULL;
    int i = 1;

    if (pos < 1 || pos > list->length + 1) {
        return 0;
    }

    node = (Node *)malloc(sizeof(Node));
    node->data = data;
    node->next = NULL;

    if (pos == 1) {
        node->next = list->head;
        list->head = node;
    } else {
        prev = list->head;
        while (prev != NULL && i < pos - 1) {
            prev = prev->next;
            i++;
        }

        node->next = prev->next;
        prev->next = node;
    }

    list->length++;

    return 1;
}

6. ListDelete：删除指定位置的节点

int ListDelete(List *list, int pos)
{
    Node *node = NULL;
    Node *prev = NULL;
    int i = 1;
    int data;

    if (pos < 1 || pos > list->length) {
        return 0;
    }

    if (pos == 1) {
        node = list->head;
        list->head = list->head->next;
    } else {
        prev = list->head;
        while (prev != NULL && i < pos - 1) {
            prev = prev->next;
            i++;
        }

        node = prev->next;
        prev->next = node->next;
    }

    data = node->data;
    free(node);
    list->length--;

    return data;
}