为一个不定长多维数字信号设计一个线性表的数据结构，并实现对其进行基本操作， 包括初始化、求数据元素个数操作、插入、删除、取数 据元素、判非空操作，并用代码实现

这个问题属于计算机科学领域，我可以回答。为不定长多维数字信号设计一个线性表的数据结构，可以使用动态数组或链表来实现。以下是使用链表实现的示例代码：

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

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

void init(List* list) {
    list->head = NULL;
    list->length = ;
}

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

void insert(List* list, int index, int data) {
    if (index <  || index > list->length) {
        return;
    }
    Node* node = (Node*)malloc(sizeof(Node));
    node->data = data;
    if (index == ) {
        node->next = list->head;
        list->head = node;
    } else {
        Node* prev = list->head;
        for (int i = ; i < index - 1; i++) {
            prev = prev->next;
        }
        node->next = prev->next;
        prev->next = node;
    }
    list->length++;
}

void remove(List* list, int index) {
    if (index <  || index >= list->length) {
        return;
    }
    Node* node;
    if (index == ) {
        node = list->head;
        list->head = node->next;
    } else {
        Node* prev = list->head;
        for (int i = ; i < index - 1; i++) {
            prev = prev->next;
        }
        node = prev->next;
        prev->next = node->next;
    }
    free(node);
    list->length--;
}

int get(List* list, int index) {
    if (index <  || index >= list->length) {
        return -1;
    }
    Node* node = list->head;
    for (int i = ; i < index; i++) {
        node = node->next;
    }
    return node->data;
}

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

使用示例：

List list;
init(&list);
insert(&list, , 1);
insert(&list, 1, 2);
insert(&list, 2, 3);
printf("size: %d\n", size(&list)); // output: size: 3
printf("get(1): %d\n", get(&list, 1)); // output: get(1): 2
remove(&list, 1);
printf("size: %d\n", size(&list)); // output: size: 2
printf("get(1): %d\n", get(&list, 1)); // output: get(1): 3
printf("isEmpty: %d\n", isEmpty(&list)); // output: isEmpty: